Merge branch 'master' into formal-verification

.changeset/beige-buses-drop.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': patch
+---
+
+`Initializable`: optimize `_disableInitializers` by using `!=` instead of `<`. ([#3787](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3787))

.changeset/config.json

@@ -0,0 +1,12 @@
+{
+  "$schema": "https://unpkg.com/@changesets/config@2.3.0/schema.json",
+  "changelog": [
+    "@changesets/changelog-github",
+    {
+      "repo": "OpenZeppelin/openzeppelin-contracts"
+    }
+  ],
+  "commit": false,
+  "access": "public",
+  "baseBranch": "master"
+}

.changeset/curvy-shrimps-enjoy.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': minor
+---
+
+`ReentrancyGuard`: Add a `_reentrancyGuardEntered` function to expose the guard status. ([#3714](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3714))

.changeset/curvy-suns-sort.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': patch
+---
+
+`Ownable2Step`: make `acceptOwnership` public virtual to enable usecases that require overriding it. ([#3960](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3960))

.changeset/early-oranges-raise.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': minor
+---
+
+`ERC721Wrapper`: add a new extension of the `ERC721` token which wraps an underlying token. Deposit and withdraw guarantee that the ownership of each token is backed by a corresponding underlying token with the same identifier.

.changeset/famous-rules-burn.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': minor
+---
+
+`EnumerableMap`: add a `keys()` function that returns an array containing all the keys. ([#3920](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3920))

.changeset/five-ducks-develop.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': patch
+---
+
+`UUPSUpgradeable.sol`: Change visibility to the functions `upgradeTo ` and `upgradeToAndCall ` from `external` to `public`.

.changeset/five-poets-mix.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': patch
+---
+
+`TimelockController`: Add the `CallSalt` event to emit on operation schedule.

.changeset/flat-deers-end.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': minor
+---
+
+`Governor`: add a public `cancel(uint256)` function.

.changeset/four-bats-sniff.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': minor
+---
+
+`Governor`: Enable timestamp operation for blockchains without a stable block time. This is achieved by connecting a Governor's internal clock to match a voting token's EIP-6372 interface.

.changeset/funny-rockets-compete.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': patch
+---
+
+Reformatted codebase with latest version of Prettier Solidity. ([#3898](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3898))

.changeset/gold-chicken-clean.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': minor
+---
+
+`Strings`: add `equal` method. ([#3774](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3774))

.changeset/happy-socks-travel.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': minor
+---
+
+`IERC5313`: Add an interface for EIP-5313 that is now final.

.changeset/healthy-squids-stare.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': patch
+---
+
+`Math`: optimize `log256` rounding check. ([#3745](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3745))

.changeset/lemon-dogs-kiss.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': patch
+---
+
+`ERC20Votes`: optimize by using unchecked arithmetic. ([#3748](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3748))

.changeset/little-kiwis-ring.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': patch
+---
+
+`Multicall`: annotate `multicall` function as upgrade safe to not raise a flag for its delegatecall. ([#3961](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3961))

.changeset/lovely-dragons-appear.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': minor
+---
+
+`IERC4906`: Add an interface for ERC-4906 that is now Final.

.changeset/many-panthers-hide.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': minor
+---
+
+`TransparentUpgradeableProxy`: support value passthrough for all ifAdmin function.

.changeset/modern-games-exist.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': minor
+---
+
+`StorageSlot`: Add support for `string` and `bytes`.

.changeset/new-ways-own.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': patch
+---
+
+`ERC20Pausable`, `ERC721Pausable`, `ERC1155Pausable`: Add note regarding missing public pausing functionality

.changeset/ninety-hornets-kick.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': minor
+---
+
+`Votes`, `ERC20Votes`, `ERC721Votes`: support timestamp checkpointing using EIP-6372.

.changeset/perfect-insects-listen.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': minor
+---
+
+`ERC4626`: Add mitigation to the inflation attack through virtual shares and assets.

.changeset/pretty-hornets-play.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': minor
+---
+
+`Strings`: add `toString` method for signed integers. ([#3773](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3773))

.changeset/proud-comics-deliver.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': minor
+---
+
+`ERC20Wrapper`: Make the `underlying` variable private and add a public accessor.

.changeset/short-roses-judge.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': minor
+---
+
+`EIP712`: add EIP-5267 support for better domain discovery.

.changeset/silent-dancers-type.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': minor
+---
+
+`AccessControlDefaultAdminRules`: Add an extension of `AccessControl` with additional security rules for the `DEFAULT_ADMIN_ROLE`.

.changeset/slimy-knives-hug.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': minor
+---
+
+`SignatureChecker`: Add `isValidERC1271SignatureNow` for checking a signature directly against a smart contract using ERC-1271.

.changeset/small-cars-appear.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': patch
+---
+
+`ECDSA`: Add a function `toDataWithIntendedValidatorHash` that encodes data with version 0x00 following EIP-191.

.changeset/small-terms-sleep.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': minor
+---
+
+`SafeERC20`: Add a `forceApprove` function to improve compatibility with tokens behaving like USDT.

.changeset/strong-bulldogs-buy.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': minor
+---
+
+`ERC1967Upgrade`: removed contract-wide `oz-upgrades-unsafe-allow delegatecall` annotation, replaced by granular annotation in `UUPSUpgradeable`.

.changeset/tame-ladybugs-sit.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': patch
+---
+
+`MerkleProof`: optimize by using unchecked arithmetic. ([#3745](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3745))

.changeset/thin-dragons-report.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': minor
+---
+
+`ECDSA`: optimize bytes32 computation by using assembly instead of `abi.encodePacked`.

.changeset/thirty-swans-exercise.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': minor
+---
+
+`ERC721URIStorage`: Emit ERC-4906 `MetadataUpdate` in `_setTokenURI`.

.changeset/violet-frogs-hide.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': minor
+---
+
+`ShortStrings`: Added a library for handling short strings in a gas efficient way, with fallback to storage for longer strings.

.changeset/warm-masks-obey.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': minor
+---
+
+`SignatureChecker`: Allow return data length greater than 32 from EIP-1271 signers.

.changeset/yellow-swans-cover.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': minor
+---
+
+`UUPSUpgradeable`: added granular `oz-upgrades-unsafe-allow-reachable` annotation to improve upgrade safety checks on latest version of the Upgrades Plugins (starting with `@openzeppelin/upgrades-core@1.21.0`).

.eslintrc

@@ -1,62 +1,20 @@
 {
+  "root": true,
   "extends" : [
-    "standard"
-  ],
-  "plugins": [
-    "mocha"
+    "eslint:recommended",
+    "prettier",
   ],
   "env": {
-    "browser" : true,
-    "node"    : true,
-    "mocha"   : true,
-    "jest"    : true,
+    "es2022": true,
+    "browser": true,
+    "node": true,
+    "mocha": true,
   },
   "globals" : {
-    "artifacts": false,
-    "contract": false,
-    "assert": false,
-    "web3": false,
-    "usePlugin": false,
-    "extendEnvironment": false,
-  },
-  "rules": {
-
-    // Strict mode
-    "strict": ["error", "global"],
-
-    // Code style
-    "array-bracket-spacing": ["off"],
-    "camelcase": ["error", {"properties": "always"}],
-    "comma-dangle": ["error", "always-multiline"],
-    "comma-spacing": ["error", {"before": false, "after": true}],
-    "dot-notation": ["error", {"allowKeywords": true, "allowPattern": ""}],
-    "eol-last": ["error", "always"],
-    "eqeqeq": ["error", "smart"],
-    "generator-star-spacing": ["error", "before"],
-    "indent": ["error", 2],
-    "linebreak-style": ["error", "unix"],
-    "max-len": ["error", 120, 2],
-    "no-debugger": "off",
-    "no-dupe-args": "error",
-    "no-dupe-keys": "error",
-    "no-mixed-spaces-and-tabs": ["error", "smart-tabs"],
-    "no-redeclare": ["error", {"builtinGlobals": true}],
-    "no-trailing-spaces": ["error", { "skipBlankLines": false }],
-    "no-undef": "error",
-    "no-use-before-define": "off",
-    "no-var": "error",
-    "object-curly-spacing": ["error", "always"],
-    "prefer-const": "error",
-    "quotes": ["error", "single"],
-    "semi": ["error", "always"],
-    "space-before-function-paren": ["error", "always"],
-
-    "mocha/no-exclusive-tests": ["error"],
-
-    "promise/always-return": "off",
-    "promise/avoid-new": "off",
-  },
-  "parserOptions": {
-    "ecmaVersion": 2020
+    "artifacts": "readonly",
+    "contract": "readonly",
+    "web3": "readonly",
+    "extendEnvironment": "readonly",
+    "expect": "readonly",
   }
 }

.gitattributes

@@ -1 +0,0 @@
-*.sol linguist-language=Solidity

.github/PULL_REQUEST_TEMPLATE.md

@@ -17,4 +17,4 @@ Fixes #???? <!-- Fill in with issue number -->
 
 - [ ] Tests
 - [ ] Documentation
-- [ ] Changelog entry
+- [ ] Changeset entry (run `npx changeset add`)

.github/actions/setup/action.yml

@@ -6,14 +6,13 @@ runs:
     - uses: actions/setup-node@v3
       with:
         node-version: 14.x
-        cache: npm
     - uses: actions/cache@v3
       id: cache
       with:
         path: '**/node_modules'
         key: npm-v3-${{ hashFiles('**/package-lock.json') }}
     - name: Install dependencies
-      run: npm ci --prefer-offline
+      run: npm ci
       shell: bash
       if: steps.cache.outputs.cache-hit != 'true'
       env:

.github/actions/storage-layout/action.yml

@@ -0,0 +1,55 @@
+name: Compare storage layouts
+inputs:
+  token:
+    description: github token
+    required: true
+  buildinfo:
+    description: compilation artifacts
+    required: false
+    default: artifacts/build-info/*.json
+  layout:
+    description: extracted storage layout
+    required: false
+    default: HEAD.layout.json
+  out_layout:
+    description: storage layout to upload
+    required: false
+    default: ${{ github.ref_name }}.layout.json
+  ref_layout:
+    description: storage layout for the reference branch
+    required: false
+    default: ${{ github.base_ref }}.layout.json
+
+runs:
+  using: composite
+  steps:
+    - name: Extract layout
+      run: |
+        node scripts/checks/extract-layout.js ${{ inputs.buildinfo }} > ${{ inputs.layout }}
+      shell: bash
+    - name: Download reference
+      if: github.event_name == 'pull_request'
+      run: |
+        RUN_ID=`gh run list --repo ${{ github.repository }} --branch ${{ github.base_ref }} --workflow ${{ github.workflow }} --limit 100 --json 'conclusion,databaseId,event' --jq 'map(select(.conclusion=="success" and .event!="pull_request"))[0].databaseId'`
+        gh run download ${RUN_ID} --repo ${{ github.repository }} -n layout
+      env:
+        GITHUB_TOKEN: ${{ inputs.token }}
+      shell: bash
+      continue-on-error: true
+      id: reference
+    - name: Compare layouts
+      if: steps.reference.outcome == 'success' && github.event_name == 'pull_request'
+      run: |
+        node scripts/checks/compare-layout.js --head ${{ inputs.layout }} --ref ${{ inputs.ref_layout }}
+      shell: bash
+    - name: Rename artifacts for upload
+      if: github.event_name != 'pull_request'
+      run: |
+        mv ${{ inputs.layout }} ${{ inputs.out_layout }}
+      shell: bash
+    - name: Save artifacts
+      if: github.event_name != 'pull_request'
+      uses: actions/upload-artifact@v3
+      with:
+        name: layout
+        path: ${{ inputs.out_layout }}

.github/workflows/actionlint.yml

@@ -0,0 +1,18 @@
+name: lint workflows
+
+on:
+  pull_request:
+    paths:
+      - '.github/**/*.ya?ml'
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: Add problem matchers
+        run: |
+          # https://github.com/rhysd/actionlint/blob/3a2f2c7/docs/usage.md#problem-matchers
+          curl -LO https://raw.githubusercontent.com/rhysd/actionlint/main/.github/actionlint-matcher.json
+          echo "::add-matcher::actionlint-matcher.json"
+      - uses: docker://rhysd/actionlint:latest

.github/workflows/changelog.yml

@@ -1,27 +0,0 @@
-name: Changelog
-
-on:
-  pull_request:
-    types:
-      - opened
-      - synchronize
-      - labeled
-      - unlabeled
-
-concurrency:
-  group: changelog-${{ github.ref }}
-  cancel-in-progress: true
-
-jobs:
-  check:
-    runs-on: ubuntu-latest
-    if: ${{ !contains(github.event.pull_request.labels.*.name, 'ignore-changelog') }}
-    steps:
-      - uses: actions/checkout@v3
-      - name: Check diff
-        run: |
-          git fetch origin ${{ github.base_ref }} --depth=1
-          if git diff --exit-code origin/${{ github.base_ref }} -- CHANGELOG.md ; then
-            echo 'Missing changelog entry'
-            exit 1
-          fi

.github/workflows/changeset.yml

@@ -0,0 +1,28 @@
+name: changeset
+
+on:
+  pull_request:
+    branches:
+      - master
+    types:
+      - opened
+      - synchronize
+      - labeled
+      - unlabeled
+
+concurrency:
+  group: changeset-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  check:
+    runs-on: ubuntu-latest
+    if: ${{ !contains(github.event.pull_request.labels.*.name, 'ignore-changeset') }}
+    steps:
+      - uses: actions/checkout@v3
+        with:
+          fetch-depth: 0 # Include history so Changesets finds merge-base
+      - name: Set up environment
+        uses: ./.github/actions/setup
+      - name: Check changeset
+        run: npx changeset status --since=origin/${{ github.base_ref }}

.github/workflows/checks.yml

@@ -26,6 +26,7 @@ jobs:
     runs-on: ubuntu-latest
     env:
       FORCE_COLOR: 1
+      NODE_OPTIONS: --max_old_space_size=4096
       GAS: true
     steps:
       - uses: actions/checkout@v3
@@ -42,8 +43,13 @@ jobs:
         uses: ./.github/actions/gas-compare
         with:
           token: ${{ github.token }}
+      - name: Check storage layout
+        uses: ./.github/actions/storage-layout
+        with:
+          token: ${{ github.token }}
 
   foundry-tests:
+    if: github.repository != 'OpenZeppelin/openzeppelin-contracts-upgradeable'
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
@@ -75,7 +81,8 @@ jobs:
       - uses: actions/checkout@v3
       - name: Set up environment
         uses: ./.github/actions/setup
-      - uses: crytic/slither-action@v0.1.1
+      - run: rm foundry.toml
+      - uses: crytic/slither-action@v0.3.0
 
   codespell:
     if: github.repository != 'OpenZeppelin/openzeppelin-contracts-upgradeable'
@@ -86,4 +93,4 @@ jobs:
         uses: codespell-project/actions-codespell@v1.0
         with:
           check_filenames: true
-          skip: package-lock.json
+          skip: package-lock.json,*.pdf

.github/workflows/docs.yml

@@ -4,6 +4,9 @@ on:
   push:
     branches: [release-v*]
 
+permissions:
+  contents: write
+
 jobs:
   build:
     runs-on: ubuntu-latest

.github/workflows/release-cycle.yml

@@ -0,0 +1,214 @@
+#  D: Manual Dispatch
+#  M: Merge release PR
+#  C: Commit
+#  ┌───────────┐     ┌─────────────┐     ┌────────────────┐
+#  │Development├──D──►RC-Unreleased│  ┌──►Final-Unreleased│
+#  └───────────┘     └─┬─────────▲─┘  │  └─┬────────────▲─┘
+#                      │         │    │    │            │
+#                      M         C    D    M            C
+#                      │         │    │    │            │
+#                     ┌▼─────────┴┐   │   ┌▼────────────┴┐
+#                     │RC-Released├───┘   │Final-Released│
+#                     └───────────┘       └──────────────┘
+name: Release Cycle
+
+on:
+  push:
+    branches:
+      - release-v*
+  workflow_dispatch: {}
+
+concurrency: ${{ github.workflow }}-${{ github.ref }}
+
+jobs:
+  state:
+    name: Check state
+    permissions:
+      pull-requests: read
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: Set up environment
+        uses: ./.github/actions/setup
+      - id: state
+        name: Get state
+        uses: actions/github-script@v6
+        env:
+          TRIGGERING_ACTOR: ${{ github.triggering_actor }}
+        with:
+          result-encoding: string
+          script: await require('./scripts/release/workflow/state.js')({ github, context, core })
+    outputs:
+      # Job Flags
+      start: ${{ steps.state.outputs.start }}
+      changesets: ${{ steps.state.outputs.changesets }}
+      promote: ${{ steps.state.outputs.promote }}
+      publish: ${{ steps.state.outputs.publish }}
+      merge: ${{ steps.state.outputs.merge }}
+
+      # Global variables
+      is_prerelease: ${{ steps.state.outputs.is_prerelease }}
+
+  start:
+    needs: state
+    name: Start new release candidate
+    permissions:
+      contents: write
+      actions: write
+    if: needs.state.outputs.start == 'true'
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: Set up environment
+        uses: ./.github/actions/setup
+      - run: bash scripts/git-user-config.sh
+      - id: start
+        name: Create branch with release candidate
+        run: bash scripts/release/workflow/start.sh
+      - name: Re-run workflow
+        uses: actions/github-script@v6
+        env:
+          REF: ${{ steps.start.outputs.branch }}
+        with:
+          script: await require('./scripts/release/workflow/rerun.js')({ github, context })
+
+  promote:
+    needs: state
+    name: Promote to final release
+    permissions:
+      contents: write
+      actions: write
+    if: needs.state.outputs.promote == 'true'
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: Set up environment
+        uses: ./.github/actions/setup
+      - run: bash scripts/git-user-config.sh
+      - name: Exit prerelease state
+        if: needs.state.outputs.is_prerelease == 'true'
+        run: bash scripts/release/workflow/exit-prerelease.sh
+      - name: Re-run workflow
+        uses: actions/github-script@v6
+        with:
+          script: await require('./scripts/release/workflow/rerun.js')({ github, context })
+
+  changesets:
+    needs: state
+    name: Update PR to release
+    permissions:
+      contents: write
+      pull-requests: write
+    if: needs.state.outputs.changesets == 'true'
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+        with:
+          fetch-depth: 0 # To get all tags
+      - name: Set up environment
+        uses: ./.github/actions/setup
+      - name: Set release title
+        uses: actions/github-script@v6
+        with:
+          result-encoding: string
+          script: await require('./scripts/release/workflow/set-changesets-pr-title.js')({ core })
+      - name: Create PR
+        uses: changesets/action@v1
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          PRERELEASE: ${{ needs.state.outputs.is_prerelease }}
+        with:
+          version: npm run version
+          title: ${{ env.TITLE }}
+          commit: ${{ env.TITLE }}
+          body: | # Wait for support on this https://github.com/changesets/action/pull/250
+            This is an automated PR for releasing ${{ github.repository }}
+            Check [CHANGELOG.md](${{ github.repository }}/CHANGELOG.md)
+
+  publish:
+    needs: state
+    name: Publish to npm
+    environment: npm
+    permissions:
+      contents: write
+    if: needs.state.outputs.publish == 'true'
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: Set up environment
+        uses: ./.github/actions/setup
+      - id: pack
+        name: Pack
+        run: bash scripts/release/workflow/pack.sh
+        env:
+          PRERELEASE: ${{ needs.state.outputs.is_prerelease }}
+      - name: Upload tarball artifact
+        uses: actions/upload-artifact@v3
+        with:
+          name: ${{ github.ref_name }}
+          path: ${{ steps.pack.outputs.tarball }}
+      - name: Tag
+        run: npx changeset tag
+      - name: Publish
+        run: bash scripts/release/workflow/publish.sh
+        env:
+          NPM_TOKEN: ${{ secrets.NPM_TOKEN }}
+          TARBALL: ${{ steps.pack.outputs.tarball }}
+          TAG: ${{ steps.pack.outputs.tag }}
+      - name: Push tags
+        run: git push --tags
+      - name: Create Github Release
+        uses: actions/github-script@v6
+        env:
+          PRERELEASE: ${{ needs.state.outputs.is_prerelease }}
+        with:
+          script: await require('./scripts/release/workflow/github-release.js')({ github, context })
+    outputs:
+      tarball_name: ${{ steps.pack.outputs.tarball_name }}
+
+  integrity_check:
+    needs: publish
+    name: Tarball Integrity Check
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: Download tarball artifact
+        id: artifact
+        # Replace with actions/upload-artifact@v3 when
+        # https://github.com/actions/download-artifact/pull/194 gets released
+        uses: actions/download-artifact@e9ef242655d12993efdcda9058dee2db83a2cb9b
+        with:
+          name: ${{ github.ref_name }}
+      - name: Check integrity
+        run: bash scripts/release/workflow/integrity-check.sh
+        env:
+          TARBALL: ${{ steps.artifact.outputs.download-path }}/${{ needs.publish.outputs.tarball_name }}
+
+  merge:
+    needs: state
+    name: Create PR back to master
+    permissions:
+      contents: write
+      pull-requests: write
+    if: needs.state.outputs.merge == 'true'
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+        with:
+          fetch-depth: 0 # All branches
+      - name: Set up environment
+        uses: ./.github/actions/setup
+      - run: bash scripts/git-user-config.sh
+      - name: Create branch to merge
+        run: bash scripts/release/workflow/prepare-release-merge.sh
+      - name: Create PR back to master
+        uses: actions/github-script@v6
+        with:
+          script: |
+            await github.rest.pulls.create({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              head: 'merge/${{ github.ref_name }}',
+              base: 'master',
+              title: '${{ format('Merge {0} branch', github.ref_name) }}'
+            });

.github/workflows/upgradeable.yml

@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - id: app
-        uses: getsentry/action-github-app-token@v1
+        uses: getsentry/action-github-app-token@v2
         with:
           app_id: ${{ secrets.UPGRADEABLE_APP_ID }}
           private_key: ${{ secrets.UPGRADEABLE_APP_PK }}

.gitignore

@@ -54,9 +54,15 @@ allFiredEvents
 .coverage_cache
 .coverage_contracts
 
-# hardhat
-cache
-artifacts
+# hardat-exposed
+contracts-exposed
+
+# Hardhat
+/cache
+/artifacts
+
+# Foundry
+/out
 
 # Certora
 .certora*

.gitmodules

@@ -1,3 +1,6 @@
 [submodule "lib/forge-std"]
 	path = lib/forge-std
 	url = https://github.com/foundry-rs/forge-std
+[submodule "lib/erc4626-tests"]
+	path = lib/erc4626-tests
+	url = https://github.com/a16z/erc4626-tests.git

.prettierrc

@@ -1,13 +1,13 @@
 {
+  "printWidth": 120,
   "singleQuote": true,
   "trailingComma": "all",
+  "arrowParens": "avoid",
   "overrides": [
     {
       "files": "*.sol",
       "options": {
-        "singleQuote": false,
-        "printWidth": 120,
-        "explicitTypes": "always"
+        "singleQuote": false
       }
     }
   ]

.solcover.js

@@ -1,15 +1,13 @@
 module.exports = {
-    norpc: true,
-    testCommand: 'npm test',
-    compileCommand: 'npm run compile',
-    skipFiles: [
-        'mocks',
-    ],
-    providerOptions: {
-        default_balance_ether: '10000000000000000000000000',
-    },
-    mocha: {
-        fgrep: '[skip-on-coverage]',
-        invert: true,
-    },
-}
+  norpc: true,
+  testCommand: 'npm test',
+  compileCommand: 'npm run compile',
+  skipFiles: ['mocks'],
+  providerOptions: {
+    default_balance_ether: '10000000000000000000000000',
+  },
+  mocha: {
+    fgrep: '[skip-on-coverage]',
+    invert: true,
+  },
+};

CHANGELOG.md

@@ -1,170 +1,222 @@
 # Changelog
 
-## Unreleased
-
- * `Initializable`: add internal functions `_getInitializedVersion` and `_isInitializing` ([#3598](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3598))
- * `ERC165Checker`: add `supportsERC165InterfaceUnchecked` for consulting individual interfaces without the full ERC165 protocol. ([#3339](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3339))
- * `Address`: optimize `functionCall` by calling `functionCallWithValue` directly. ([#3468](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3468))
- * `Address`: optimize `functionCall` functions by checking contract size only if there is no returned data. ([#3469](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3469))
- * `GovernorCompatibilityBravo`: remove unused `using` statements. ([#3506](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3506))
- * `ERC20`: optimize `_transfer`, `_mint` and `_burn` by using `unchecked` arithmetic when possible. ([#3513](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3513))
- * `ERC20Votes`, `ERC721Votes`: optimize `getPastVotes` for looking up recent checkpoints. ([#3673](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3673))
- * `ERC20FlashMint`: add an internal `_flashFee` function for overriding. ([#3551](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3551))
- * `ERC4626`: use the same `decimals()` as the underlying asset by default (if available). ([#3639](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3639))
- * `ERC4626`: add internal `_initialConvertToShares` and `_initialConvertToAssets` functions to customize empty vaults behavior. ([#3639](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3639))
- * `ERC721`: optimize transfers by making approval clearing implicit instead of emitting an event. ([#3481](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3481))
- * `ERC721`: optimize burn by making approval clearing implicit instead of emitting an event. ([#3538](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3538))
- * `ERC721`: Fix balance accounting when a custom `_beforeTokenTransfer` hook results in a transfer of the token under consideration. ([#3611](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3611))
- * `ERC721`: use unchecked arithmetic for balance updates. ([#3524](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3524))
- * `ERC721Consecutive`: Implementation of EIP-2309 that allows batch minting of ERC721 tokens during construction. ([#3311](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3311))
- * `ReentrancyGuard`: Reduce code size impact of the modifier by using internal functions. ([#3515](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3515))
- * `SafeCast`: optimize downcasting of signed integers. ([#3565](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3565))
- * `ECDSA`: Remove redundant check on the `v` value. ([#3591](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3591))
- * `VestingWallet`: add `releasable` getters. ([#3580](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3580))
- * `VestingWallet`: remove unused library `Math.sol`. ([#3605](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3605))
- * `VestingWallet`: make constructor payable. ([#3665](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3665))
- * `Create2`: optimize address computation by using assembly instead of `abi.encodePacked`. ([#3600](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3600))
- * `Clones`: optimized the assembly to use only the scratch space during deployments, and optimized `predictDeterministicAddress` to use fewer operations. ([#3640](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3640))
- * `Checkpoints`: Use procedural generation to support multiple key/value lengths. ([#3589](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3589))
- * `Checkpoints`: Add new lookup mechanisms. ([#3589](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3589))
- * `Arrays`: Add `unsafeAccess` functions that allow reading and writing to an element in a storage array bypassing Solidity's "out-of-bounds" check. ([#3589](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3589))
- * `Strings`: optimize `toString`. ([#3573](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3573))
- * `Ownable2Step`: extension of `Ownable` that makes the ownership transfers a two step process. ([#3620](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3620))
- * `Math` and `SignedMath`: optimize function `max` by using `>` instead of `>=`. ([#3679](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3679))
- * `Math`: Add `log2`, `log10` and `log256`. ([#3670](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3670))
+### Breaking changes
+
+- `EIP712`: Addition of ERC5267 support requires support for user defined value types, which was released in Solidity version 0.8.8. This requires a pragma change from `^0.8.0` to `^0.8.8`.
+- `EIP712`: Optimization of the cache for the upgradeable version affects the way `name` and `version` are set. This is no longer done through an initializer, and is instead part of the implementation's constructor. As a consequence, all proxies using the same implementation will necessarily share the same `name` and `version`. Additionally, an implementation upgrade risks changing the EIP712 domain unless the same `name` and `version` are used when deploying the new implementation contract.
+
+### Deprecations
+
+- `ERC20Permit`: Added the file `IERC20Permit.sol` and `ERC20Permit.sol` and deprecated `draft-IERC20Permit.sol` and `draft-ERC20Permit.sol` since [EIP-2612](https://eips.ethereum.org/EIPS/eip-2612) is no longer a Draft. Developers are encouraged to update their imports. ([#3793](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3793))
+- `Timers`: The `Timers` library is now deprecated and will be removed in the next major release. ([#4062](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/4062))
+- `ERC777`: The `ERC777` token standard is no longer supported by OpenZeppelin. Our implementation is now deprecated and will be removed in the next major release. The corresponding standard interfaces remain available. ([#4066](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/4066))
+- `ERC1820Implementer`: The `ERC1820` pseudo-introspection mechanism is no longer supported by OpenZeppelin. Our implementation is now deprecated and will be removed in the next major release. The corresponding standard interfaces remain available. ([#4066](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/4066))
+
+## 4.8.1 (2023-01-12)
+
+- `ERC4626`: Use staticcall instead of call when fetching underlying ERC-20 decimals. ([#3943](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3943))
+
+## 4.8.0 (2022-11-08)
+
+- `TimelockController`: Added a new `admin` constructor parameter that is assigned the admin role instead of the deployer account. ([#3722](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3722))
+- `Initializable`: add internal functions `_getInitializedVersion` and `_isInitializing` ([#3598](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3598))
+- `ERC165Checker`: add `supportsERC165InterfaceUnchecked` for consulting individual interfaces without the full ERC165 protocol. ([#3339](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3339))
+- `Address`: optimize `functionCall` by calling `functionCallWithValue` directly. ([#3468](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3468))
+- `Address`: optimize `functionCall` functions by checking contract size only if there is no returned data. ([#3469](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3469))
+- `Governor`: make the `relay` function payable, and add support for EOA payments. ([#3730](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3730))
+- `GovernorCompatibilityBravo`: remove unused `using` statements. ([#3506](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3506))
+- `ERC20`: optimize `_transfer`, `_mint` and `_burn` by using `unchecked` arithmetic when possible. ([#3513](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3513))
+- `ERC20Votes`, `ERC721Votes`: optimize `getPastVotes` for looking up recent checkpoints. ([#3673](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3673))
+- `ERC20FlashMint`: add an internal `_flashFee` function for overriding. ([#3551](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3551))
+- `ERC4626`: use the same `decimals()` as the underlying asset by default (if available). ([#3639](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3639))
+- `ERC4626`: add internal `_initialConvertToShares` and `_initialConvertToAssets` functions to customize empty vaults behavior. ([#3639](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3639))
+- `ERC721`: optimize transfers by making approval clearing implicit instead of emitting an event. ([#3481](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3481))
+- `ERC721`: optimize burn by making approval clearing implicit instead of emitting an event. ([#3538](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3538))
+- `ERC721`: Fix balance accounting when a custom `_beforeTokenTransfer` hook results in a transfer of the token under consideration. ([#3611](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3611))
+- `ERC721`: use unchecked arithmetic for balance updates. ([#3524](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3524))
+- `ERC721Consecutive`: Implementation of EIP-2309 that allows batch minting of ERC721 tokens during construction. ([#3311](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3311))
+- `ReentrancyGuard`: Reduce code size impact of the modifier by using internal functions. ([#3515](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3515))
+- `SafeCast`: optimize downcasting of signed integers. ([#3565](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3565))
+- `ECDSA`: Remove redundant check on the `v` value. ([#3591](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3591))
+- `VestingWallet`: add `releasable` getters. ([#3580](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3580))
+- `VestingWallet`: remove unused library `Math.sol`. ([#3605](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3605))
+- `VestingWallet`: make constructor payable. ([#3665](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3665))
+- `Create2`: optimize address computation by using assembly instead of `abi.encodePacked`. ([#3600](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3600))
+- `Clones`: optimized the assembly to use only the scratch space during deployments, and optimized `predictDeterministicAddress` to use fewer operations. ([#3640](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3640))
+- `Checkpoints`: Use procedural generation to support multiple key/value lengths. ([#3589](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3589))
+- `Checkpoints`: Add new lookup mechanisms. ([#3589](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3589))
+- `Arrays`: Add `unsafeAccess` functions that allow reading and writing to an element in a storage array bypassing Solidity's "out-of-bounds" check. ([#3589](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3589))
+- `Strings`: optimize `toString`. ([#3573](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3573))
+- `Ownable2Step`: extension of `Ownable` that makes the ownership transfers a two step process. ([#3620](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3620))
+- `Math` and `SignedMath`: optimize function `max` by using `>` instead of `>=`. ([#3679](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3679))
+- `Math`: Add `log2`, `log10` and `log256`. ([#3670](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3670))
+- Arbitrum: Update the vendored arbitrum contracts to match the nitro upgrade. ([#3692](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3692))
 
 ### Breaking changes
 
- * `ERC4626`: Conversion from shares to assets (and vice-versa) in an empty vault used to consider the possible mismatch between the underlying asset's and the vault's decimals. This initial conversion rate is now set to 1-to-1 irrespective of decimals, which are meant for usability purposes only. The vault now uses the assets decimals by default, so off-chain the numbers should appear the same. Developers overriding the vault decimals to a value that does not match the underlying asset may want to override the `_initialConvertToShares` and `_initialConvertToAssets` to replicate the previous behavior.
+- `ERC721`: In order to add support for batch minting via `ERC721Consecutive` it was necessary to make a minor breaking change in the internal interface of `ERC721`. Namely, the hooks `_beforeTokenTransfer` and `_afterTokenTransfer` have one additional argument that may need to be added to overrides:
+
+```diff
+ function _beforeTokenTransfer(
+     address from,
+     address to,
+     uint256 tokenId,
++    uint256 batchSize
+ ) internal virtual override
+```
+
+- `ERC4626`: Conversion from shares to assets (and vice-versa) in an empty vault used to consider the possible mismatch between the underlying asset's and the vault's decimals. This initial conversion rate is now set to 1-to-1 irrespective of decimals, which are meant for usability purposes only. The vault now uses the assets decimals by default, so off-chain the numbers should appear the same. Developers overriding the vault decimals to a value that does not match the underlying asset may want to override the `_initialConvertToShares` and `_initialConvertToAssets` to replicate the previous behavior.
+
+- `TimelockController`: During deployment, the TimelockController used to grant the `TIMELOCK_ADMIN_ROLE` to the deployer and to the timelock itself. The deployer was then expected to renounce this role once configuration of the timelock is over. Failing to renounce that role allows the deployer to change the timelock permissions (but not to bypass the delay for any time-locked actions). The role is no longer given to the deployer by default. A new parameter `admin` can be set to a non-zero address to grant the admin role during construction (to the deployer or any other address). Just like previously, this admin role should be renounced after configuration. If this param is given `address(0)`, the role is not allocated and doesn't need to be revoked. In any case, the timelock itself continues to have this role.
 
 ### Deprecations
 
- * `EIP712`: Added the file `EIP712.sol` and deprecated `draft-EIP712.sol` since the EIP is no longer a Draft. Developers are encouraged to update their imports. ([#3621](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3621))
+- `EIP712`: Added the file `EIP712.sol` and deprecated `draft-EIP712.sol` since the EIP is no longer a Draft. Developers are encouraged to update their imports. ([#3621](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3621))
 
 ```diff
 -import "@openzeppelin/contracts/utils/cryptography/draft-EIP712.sol";
 +import "@openzeppelin/contracts/utils/cryptography/EIP712.sol";
 ```
 
+- `ERC721Votes`: Added the file `ERC721Votes.sol` and deprecated `draft-ERC721Votes.sol` since it no longer depends on a Draft EIP (EIP-712). Developers are encouraged to update their imports. ([#3699](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3699))
+
+```diff
+-import "@openzeppelin/contracts/token/ERC721/extensions/draft-ERC721Votes.sol";
++import "@openzeppelin/contracts/token/ERC721/extensions/ERC721Votes.sol";
+```
+
 ### ERC-721 Compatibility Note
 
 ERC-721 integrators that interpret contract state from events should make sure that they implement the clearing of approval that is implicit in every transfer according to the EIP. Previous versions of OpenZeppelin Contracts emitted an explicit `Approval` event even though it was not required by the specification, and this is no longer the case.
 
-With the new `ERC721Consecutive` extension, the internal workings of `ERC721` are slightly changed. Custom extensions to ERC721 should be reviewed to ensure they remain correct. The new internal functions that should be considered are `_ownerOf`, `_beforeConsecutiveTokenTransfer`, and `_afterConsecutiveTokenTransfer`, and the existing internal functions that should be reviewed are `_exists`, `_beforeTokenTransfer`, and `_afterTokenTransfer`.
+With the new `ERC721Consecutive` extension, the internal workings of `ERC721` are slightly changed. Custom extensions to ERC721 should be reviewed to ensure they remain correct. The internal functions that should be considered are `_ownerOf` (new), `_beforeTokenTransfer`, and `_afterTokenTransfer`.
 
-## 4.7.3
+### ERC-4626 Upgrade Note
+
+Existing `ERC4626` contracts that are upgraded to 4.8 must initialize a new variable that holds the vault token decimals. The recommended way to do this is to use a [reinitializer]:
+
+[reinitializer]: https://docs.openzeppelin.com/contracts/4.x/api/proxy#Initializable-reinitializer-uint8-
+
+```solidity
+function migrateToV48() public reinitializer(2) {
+  __ERC4626_init(IERC20Upgradeable(asset()));
+}
+```
+
+## 4.7.3 (2022-08-10)
 
 ### Breaking changes
 
- * `ECDSA`: `recover(bytes32,bytes)` and `tryRecover(bytes32,bytes)` no longer accept compact signatures to prevent malleability. Compact signature support remains available using `recover(bytes32,bytes32,bytes32)` and `tryRecover(bytes32,bytes32,bytes32)`.
+- `ECDSA`: `recover(bytes32,bytes)` and `tryRecover(bytes32,bytes)` no longer accept compact signatures to prevent malleability. Compact signature support remains available using `recover(bytes32,bytes32,bytes32)` and `tryRecover(bytes32,bytes32,bytes32)`.
 
-## 4.7.2
+## 4.7.2 (2022-07-25)
 
- * `LibArbitrumL2`, `CrossChainEnabledArbitrumL2`: Fixed detection of cross-chain calls for EOAs. Previously, calls from EOAs would be classified as cross-chain calls. ([#3578](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3578))
- * `GovernorVotesQuorumFraction`: Fixed quorum updates so they do not affect past proposals that failed due to lack of quorum. ([#3561](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3561))
- * `ERC165Checker`: Added protection against large returndata. ([#3587](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3587))
+- `LibArbitrumL2`, `CrossChainEnabledArbitrumL2`: Fixed detection of cross-chain calls for EOAs. Previously, calls from EOAs would be classified as cross-chain calls. ([#3578](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3578))
+- `GovernorVotesQuorumFraction`: Fixed quorum updates so they do not affect past proposals that failed due to lack of quorum. ([#3561](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3561))
+- `ERC165Checker`: Added protection against large returndata. ([#3587](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3587))
 
-## 4.7.1
+## 4.7.1 (2022-07-18)
 
- * `SignatureChecker`: Fix an issue that causes `isValidSignatureNow` to revert when the target contract returns ill-encoded data. ([#3552](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3552))
- * `ERC165Checker`: Fix an issue that causes `supportsInterface` to revert when the target contract returns ill-encoded data. ([#3552](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3552))
+- `SignatureChecker`: Fix an issue that causes `isValidSignatureNow` to revert when the target contract returns ill-encoded data. ([#3552](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3552))
+- `ERC165Checker`: Fix an issue that causes `supportsInterface` to revert when the target contract returns ill-encoded data. ([#3552](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3552))
 
 ## 4.7.0 (2022-06-29)
 
- * `TimelockController`: Migrate `_call` to `_execute` and allow inheritance and overriding similar to `Governor`. ([#3317](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3317))
- * `CrossChainEnabledPolygonChild`: replace the `require` statement with the custom error `NotCrossChainCall`. ([#3380](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3380))
- * `ERC20FlashMint`: Add customizable flash fee receiver. ([#3327](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3327))
- * `ERC4626`: add an extension of `ERC20` that implements the ERC4626 Tokenized Vault Standard. ([#3171](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3171))
- * `SafeERC20`: add `safePermit` as mitigation against phantom permit functions. ([#3280](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3280))
- * `Math`: add a `mulDiv` function that can round the result either up or down. ([#3171](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3171))
- * `Math`: Add a `sqrt` function to compute square roots of integers, rounding either up or down. ([#3242](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3242))
- * `Strings`: add a new overloaded function `toHexString` that converts an `address` with fixed length of 20 bytes to its not checksummed ASCII `string` hexadecimal representation. ([#3403](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3403))
- * `EnumerableMap`: add new `UintToUintMap` map type. ([#3338](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3338))
- * `EnumerableMap`: add new `Bytes32ToUintMap` map type. ([#3416](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3416))
- * `SafeCast`: add support for many more types, using procedural code generation. ([#3245](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3245))
- * `MerkleProof`: add `multiProofVerify` to prove multiple values are part of a Merkle tree. ([#3276](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3276))
- * `MerkleProof`: add calldata versions of the functions to avoid copying input arrays to memory and save gas. ([#3200](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3200))
- * `ERC721`, `ERC1155`: simplified revert reasons. ([#3254](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3254), ([#3438](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3438)))
- * `ERC721`: removed redundant require statement. ([#3434](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3434))
- * `PaymentSplitter`: add `releasable` getters. ([#3350](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3350))
- * `Initializable`: refactored implementation of modifiers for easier understanding. ([#3450](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3450))
- * `Proxies`: remove runtime check of ERC1967 storage slots. ([#3455](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3455))
+- `TimelockController`: Migrate `_call` to `_execute` and allow inheritance and overriding similar to `Governor`. ([#3317](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3317))
+- `CrossChainEnabledPolygonChild`: replace the `require` statement with the custom error `NotCrossChainCall`. ([#3380](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3380))
+- `ERC20FlashMint`: Add customizable flash fee receiver. ([#3327](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3327))
+- `ERC4626`: add an extension of `ERC20` that implements the ERC4626 Tokenized Vault Standard. ([#3171](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3171))
+- `SafeERC20`: add `safePermit` as mitigation against phantom permit functions. ([#3280](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3280))
+- `Math`: add a `mulDiv` function that can round the result either up or down. ([#3171](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3171))
+- `Math`: Add a `sqrt` function to compute square roots of integers, rounding either up or down. ([#3242](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3242))
+- `Strings`: add a new overloaded function `toHexString` that converts an `address` with fixed length of 20 bytes to its not checksummed ASCII `string` hexadecimal representation. ([#3403](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3403))
+- `EnumerableMap`: add new `UintToUintMap` map type. ([#3338](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3338))
+- `EnumerableMap`: add new `Bytes32ToUintMap` map type. ([#3416](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3416))
+- `SafeCast`: add support for many more types, using procedural code generation. ([#3245](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3245))
+- `MerkleProof`: add `multiProofVerify` to prove multiple values are part of a Merkle tree. ([#3276](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3276))
+- `MerkleProof`: add calldata versions of the functions to avoid copying input arrays to memory and save gas. ([#3200](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3200))
+- `ERC721`, `ERC1155`: simplified revert reasons. ([#3254](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3254), ([#3438](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3438)))
+- `ERC721`: removed redundant require statement. ([#3434](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3434))
+- `PaymentSplitter`: add `releasable` getters. ([#3350](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3350))
+- `Initializable`: refactored implementation of modifiers for easier understanding. ([#3450](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3450))
+- `Proxies`: remove runtime check of ERC1967 storage slots. ([#3455](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3455))
 
 ### Breaking changes
 
- * `Initializable`: functions decorated with the modifier `reinitializer(1)` may no longer invoke each other.
+- `Initializable`: functions decorated with the modifier `reinitializer(1)` may no longer invoke each other.
 
 ## 4.6.0 (2022-04-26)
 
- * `crosschain`: Add a new set of contracts for cross-chain applications. `CrossChainEnabled` is a base contract with instantiations for several chains and bridges, and `AccessControlCrossChain` is an extension of access control that allows cross-chain operation. ([#3183](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3183))
- * `AccessControl`: add a virtual `_checkRole(bytes32)` function that can be overridden to alter the `onlyRole` modifier behavior. ([#3137](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3137))
- * `EnumerableMap`: add new `AddressToUintMap` map type. ([#3150](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3150))
- * `EnumerableMap`: add new `Bytes32ToBytes32Map` map type. ([#3192](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3192))
- * `ERC20FlashMint`: support infinite allowance when paying back a flash loan. ([#3226](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3226))
- * `ERC20Wrapper`: the `decimals()` function now tries to fetch the value from the underlying token instance. If that calls revert, then the default value is used. ([#3259](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3259))
- * `draft-ERC20Permit`: replace `immutable` with `constant` for `_PERMIT_TYPEHASH` since the `keccak256` of string literals is treated specially and the hash is evaluated at compile time. ([#3196](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3196))
- * `ERC1155`: Add a `_afterTokenTransfer` hook for improved extensibility. ([#3166](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3166))
- * `ERC1155URIStorage`: add a new extension that implements a `_setURI` behavior similar to ERC721's `_setTokenURI`. ([#3210](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3210))
- * `DoubleEndedQueue`: a new data structure that supports efficient push and pop to both front and back, useful for FIFO and LIFO queues. ([#3153](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3153))
- * `Governor`: improved security of `onlyGovernance` modifier when using an external executor contract (e.g. a timelock) that can operate without necessarily going through the governance protocol. ([#3147](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3147))
- * `Governor`: Add a way to parameterize votes. This can be used to implement voting systems such as fractionalized voting, ERC721 based voting, or any number of other systems. The `params` argument added to `_countVote` method, and included in the newly added `_getVotes` method, can be used by counting and voting modules respectively for such purposes. ([#3043](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3043))
- * `Governor`: rewording of revert reason for consistency. ([#3275](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3275))
- * `Governor`: fix an inconsistency in data locations that could lead to invalid bytecode being produced. ([#3295](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3295))
- * `Governor`: Implement `IERC721Receiver` and `IERC1155Receiver` to improve token custody by governors. ([#3230](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3230))
- * `TimelockController`: Implement `IERC721Receiver` and `IERC1155Receiver` to improve token custody by timelocks. ([#3230](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3230))
- * `TimelockController`: Add a separate canceller role for the ability to cancel. ([#3165](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3165))
- * `Initializable`: add a reinitializer modifier that enables the initialization of new modules, added to already initialized contracts through upgradeability. ([#3232](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3232))
- * `Initializable`: add an Initialized event that tracks initialized version numbers. ([#3294](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3294))
- * `ERC2981`: make `royaltyInfo` public to allow super call in overrides. ([#3305](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3305))
+- `crosschain`: Add a new set of contracts for cross-chain applications. `CrossChainEnabled` is a base contract with instantiations for several chains and bridges, and `AccessControlCrossChain` is an extension of access control that allows cross-chain operation. ([#3183](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3183))
+- `AccessControl`: add a virtual `_checkRole(bytes32)` function that can be overridden to alter the `onlyRole` modifier behavior. ([#3137](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3137))
+- `EnumerableMap`: add new `AddressToUintMap` map type. ([#3150](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3150))
+- `EnumerableMap`: add new `Bytes32ToBytes32Map` map type. ([#3192](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3192))
+- `ERC20FlashMint`: support infinite allowance when paying back a flash loan. ([#3226](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3226))
+- `ERC20Wrapper`: the `decimals()` function now tries to fetch the value from the underlying token instance. If that calls revert, then the default value is used. ([#3259](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3259))
+- `draft-ERC20Permit`: replace `immutable` with `constant` for `_PERMIT_TYPEHASH` since the `keccak256` of string literals is treated specially and the hash is evaluated at compile time. ([#3196](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3196))
+- `ERC1155`: Add a `_afterTokenTransfer` hook for improved extensibility. ([#3166](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3166))
+- `ERC1155URIStorage`: add a new extension that implements a `_setURI` behavior similar to ERC721's `_setTokenURI`. ([#3210](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3210))
+- `DoubleEndedQueue`: a new data structure that supports efficient push and pop to both front and back, useful for FIFO and LIFO queues. ([#3153](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3153))
+- `Governor`: improved security of `onlyGovernance` modifier when using an external executor contract (e.g. a timelock) that can operate without necessarily going through the governance protocol. ([#3147](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3147))
+- `Governor`: Add a way to parameterize votes. This can be used to implement voting systems such as fractionalized voting, ERC721 based voting, or any number of other systems. The `params` argument added to `_countVote` method, and included in the newly added `_getVotes` method, can be used by counting and voting modules respectively for such purposes. ([#3043](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3043))
+- `Governor`: rewording of revert reason for consistency. ([#3275](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3275))
+- `Governor`: fix an inconsistency in data locations that could lead to invalid bytecode being produced. ([#3295](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3295))
+- `Governor`: Implement `IERC721Receiver` and `IERC1155Receiver` to improve token custody by governors. ([#3230](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3230))
+- `TimelockController`: Implement `IERC721Receiver` and `IERC1155Receiver` to improve token custody by timelocks. ([#3230](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3230))
+- `TimelockController`: Add a separate canceller role for the ability to cancel. ([#3165](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3165))
+- `Initializable`: add a reinitializer modifier that enables the initialization of new modules, added to already initialized contracts through upgradeability. ([#3232](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3232))
+- `Initializable`: add an Initialized event that tracks initialized version numbers. ([#3294](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3294))
+- `ERC2981`: make `royaltyInfo` public to allow super call in overrides. ([#3305](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3305))
 
 ### Upgradeability notice
 
-* `TimelockController`: **(Action needed)** The upgrade from <4.6 to >=4.6 introduces a new `CANCELLER_ROLE` that requires set up to be assignable. After the upgrade, only addresses with this role will have the ability to cancel. Proposers will no longer be able to cancel. Assigning cancellers can be done by an admin (including the timelock itself) once the role admin is set up. To do this, we recommend upgrading to the `TimelockControllerWith46MigrationUpgradeable` contract and then calling the `migrateTo46` function.
+- `TimelockController`: **(Action needed)** The upgrade from <4.6 to >=4.6 introduces a new `CANCELLER_ROLE` that requires set up to be assignable. After the upgrade, only addresses with this role will have the ability to cancel. Proposers will no longer be able to cancel. Assigning cancellers can be done by an admin (including the timelock itself) once the role admin is set up. To do this, we recommend upgrading to the `TimelockControllerWith46MigrationUpgradeable` contract and then calling the `migrateTo46` function.
 
 ### Breaking changes
 
-* `Governor`: Adds internal virtual `_getVotes` method that must be implemented; this is a breaking change for existing concrete extensions to `Governor`. To fix this on an existing voting module extension, rename `getVotes` to `_getVotes` and add a `bytes memory` argument. ([#3043](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3043))
-* `Governor`: Adds `params` parameter to internal virtual `_countVote` method; this is a breaking change for existing concrete extensions to `Governor`. To fix this on an existing counting module extension, add a `bytes memory` argument to `_countVote`. ([#3043](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3043))
-* `Governor`: Does not emit `VoteCast` event when params data is non-empty; instead emits `VoteCastWithParams` event. To fix this on an integration that consumes the `VoteCast` event, also fetch/monitor `VoteCastWithParams` events. ([#3043](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3043))
-* `Votes`: The internal virtual function `_getVotingUnits` was made `view` (which was accidentally missing). Any overrides should now be updated so they are `view` as well.
+- `Governor`: Adds internal virtual `_getVotes` method that must be implemented; this is a breaking change for existing concrete extensions to `Governor`. To fix this on an existing voting module extension, rename `getVotes` to `_getVotes` and add a `bytes memory` argument. ([#3043](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3043))
+- `Governor`: Adds `params` parameter to internal virtual `_countVote` method; this is a breaking change for existing concrete extensions to `Governor`. To fix this on an existing counting module extension, add a `bytes memory` argument to `_countVote`. ([#3043](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3043))
+- `Governor`: Does not emit `VoteCast` event when params data is non-empty; instead emits `VoteCastWithParams` event. To fix this on an integration that consumes the `VoteCast` event, also fetch/monitor `VoteCastWithParams` events. ([#3043](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3043))
+- `Votes`: The internal virtual function `_getVotingUnits` was made `view` (which was accidentally missing). Any overrides should now be updated so they are `view` as well.
 
 ## 4.5.0 (2022-02-09)
 
- * `ERC2981`: add implementation of the royalty standard, and the respective extensions for `ERC721` and `ERC1155`. ([#3012](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3012))
- * `GovernorTimelockControl`: improve the `state()` function to have it reflect cases where a proposal has been canceled directly on the timelock. ([#2977](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2977))
- * Preset contracts are now deprecated in favor of [Contracts Wizard](https://wizard.openzeppelin.com). ([#2986](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2986))
- * `Governor`: add a relay function to help recover assets sent to a governor that is not its own executor (e.g. when using a timelock). ([#2926](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2926))
- * `GovernorPreventLateQuorum`: add new module to ensure a minimum voting duration is available after the quorum is reached. ([#2973](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2973))
- * `ERC721`: improved revert reason when transferring from wrong owner. ([#2975](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2975))
- * `Votes`: Added a base contract for vote tracking with delegation. ([#2944](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2944))
- * `ERC721Votes`: Added an extension of ERC721 enabled with vote tracking and delegation. ([#2944](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2944))
- * `ERC2771Context`: use immutable storage to store the forwarder address, no longer an issue since Solidity >=0.8.8 allows reading immutable variables in the constructor. ([#2917](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2917))
- * `Base64`: add a library to parse bytes into base64 strings using `encode(bytes memory)` function, and provide examples to show how to use to build URL-safe `tokenURIs`. ([#2884](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2884))
- * `ERC20`: reduce allowance before triggering transfer. ([#3056](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3056))
- * `ERC20`: do not update allowance on `transferFrom` when allowance is `type(uint256).max`. ([#3085](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3085))
- * `ERC20`: add a `_spendAllowance` internal function. ([#3170](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3170))
- * `ERC20Burnable`: do not update allowance on `burnFrom` when allowance is `type(uint256).max`. ([#3170](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3170))
- * `ERC777`: do not update allowance on `transferFrom` when allowance is `type(uint256).max`. ([#3085](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3085))
- * `ERC777`: add a `_spendAllowance` internal function. ([#3170](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3170))
- * `SignedMath`: a new signed version of the Math library with `max`, `min`,  and `average`. ([#2686](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2686))
- * `SignedMath`: add an `abs(int256)` method that returns the unsigned absolute value of a signed value. ([#2984](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2984))
- * `ERC1967Upgrade`: Refactor the secure upgrade to use `ERC1822` instead of the previous rollback mechanism. This reduces code complexity and attack surface with similar security guarantees. ([#3021](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3021))
- * `UUPSUpgradeable`: Add `ERC1822` compliance to support the updated secure upgrade mechanism. ([#3021](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3021))
- * Some more functions have been made virtual to customize them via overrides. In many cases this will not imply that other functions in the contract will automatically adapt to the overridden definitions. People who wish to override should consult the source code to understand the impact and if they need to override any additional functions to achieve the desired behavior.
+- `ERC2981`: add implementation of the royalty standard, and the respective extensions for `ERC721` and `ERC1155`. ([#3012](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3012))
+- `GovernorTimelockControl`: improve the `state()` function to have it reflect cases where a proposal has been canceled directly on the timelock. ([#2977](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2977))
+- Preset contracts are now deprecated in favor of [Contracts Wizard](https://wizard.openzeppelin.com). ([#2986](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2986))
+- `Governor`: add a relay function to help recover assets sent to a governor that is not its own executor (e.g. when using a timelock). ([#2926](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2926))
+- `GovernorPreventLateQuorum`: add new module to ensure a minimum voting duration is available after the quorum is reached. ([#2973](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2973))
+- `ERC721`: improved revert reason when transferring from wrong owner. ([#2975](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2975))
+- `Votes`: Added a base contract for vote tracking with delegation. ([#2944](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2944))
+- `ERC721Votes`: Added an extension of ERC721 enabled with vote tracking and delegation. ([#2944](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2944))
+- `ERC2771Context`: use immutable storage to store the forwarder address, no longer an issue since Solidity >=0.8.8 allows reading immutable variables in the constructor. ([#2917](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2917))
+- `Base64`: add a library to parse bytes into base64 strings using `encode(bytes memory)` function, and provide examples to show how to use to build URL-safe `tokenURIs`. ([#2884](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2884))
+- `ERC20`: reduce allowance before triggering transfer. ([#3056](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3056))
+- `ERC20`: do not update allowance on `transferFrom` when allowance is `type(uint256).max`. ([#3085](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3085))
+- `ERC20`: add a `_spendAllowance` internal function. ([#3170](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3170))
+- `ERC20Burnable`: do not update allowance on `burnFrom` when allowance is `type(uint256).max`. ([#3170](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3170))
+- `ERC777`: do not update allowance on `transferFrom` when allowance is `type(uint256).max`. ([#3085](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3085))
+- `ERC777`: add a `_spendAllowance` internal function. ([#3170](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3170))
+- `SignedMath`: a new signed version of the Math library with `max`, `min`, and `average`. ([#2686](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2686))
+- `SignedMath`: add an `abs(int256)` method that returns the unsigned absolute value of a signed value. ([#2984](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2984))
+- `ERC1967Upgrade`: Refactor the secure upgrade to use `ERC1822` instead of the previous rollback mechanism. This reduces code complexity and attack surface with similar security guarantees. ([#3021](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3021))
+- `UUPSUpgradeable`: Add `ERC1822` compliance to support the updated secure upgrade mechanism. ([#3021](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3021))
+- Some more functions have been made virtual to customize them via overrides. In many cases this will not imply that other functions in the contract will automatically adapt to the overridden definitions. People who wish to override should consult the source code to understand the impact and if they need to override any additional functions to achieve the desired behavior.
 
 ### Breaking changes
 
-* `ERC1967Upgrade`: The function `_upgradeToAndCallSecure` was renamed to `_upgradeToAndCallUUPS`, along with the change in security mechanism described above.
-* `Address`: The Solidity pragma is increased from `^0.8.0` to `^0.8.1`. This is required by the `account.code.length` syntax that replaces inline assembly. This may require users to bump their compiler version from `0.8.0` to `0.8.1` or later. Note that other parts of the code already include stricter requirements.
+- `ERC1967Upgrade`: The function `_upgradeToAndCallSecure` was renamed to `_upgradeToAndCallUUPS`, along with the change in security mechanism described above.
+- `Address`: The Solidity pragma is increased from `^0.8.0` to `^0.8.1`. This is required by the `account.code.length` syntax that replaces inline assembly. This may require users to bump their compiler version from `0.8.0` to `0.8.1` or later. Note that other parts of the code already include stricter requirements.
 
 ## 4.4.2 (2022-01-11)
 
 ### Bugfixes
- * `GovernorCompatibilityBravo`: Fix error in the encoding of calldata for proposals submitted through the compatibility interface with explicit signatures. ([#3100](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3100))
+
+- `GovernorCompatibilityBravo`: Fix error in the encoding of calldata for proposals submitted through the compatibility interface with explicit signatures. ([#3100](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3100))
 
 ## 4.4.1 (2021-12-14)
 
- * `Initializable`: change the existing `initializer` modifier and add a new `onlyInitializing` modifier to prevent reentrancy risk. ([#3006](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3006))
+- `Initializable`: change the existing `initializer` modifier and add a new `onlyInitializing` modifier to prevent reentrancy risk. ([#3006](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3006))
 
 ### Breaking change
 
@@ -184,59 +236,59 @@ It is no longer possible to call an `initializer`-protected function from within
 
 ## 4.4.0 (2021-11-25)
 
- * `Ownable`: add an internal `_transferOwnership(address)`. ([#2568](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2568))
- * `AccessControl`: add internal `_grantRole(bytes32,address)` and `_revokeRole(bytes32,address)`. ([#2568](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2568))
- * `AccessControl`: mark `_setupRole(bytes32,address)` as deprecated in favor of `_grantRole(bytes32,address)`. ([#2568](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2568))
- * `AccessControlEnumerable`: hook into `_grantRole(bytes32,address)` and `_revokeRole(bytes32,address)`. ([#2946](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2946))
- * `EIP712`: cache `address(this)` to immutable storage to avoid potential issues if a vanilla contract is used in a delegatecall context. ([#2852](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2852))
- * Add internal `_setApprovalForAll` to `ERC721` and `ERC1155`. ([#2834](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2834))
- * `Governor`: shift vote start and end by one block to better match Compound's GovernorBravo and prevent voting at the Governor level if the voting snapshot is not ready. ([#2892](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2892))
- * `GovernorCompatibilityBravo`: consider quorum an inclusive rather than exclusive minimum to match Compound's GovernorBravo. ([#2974](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2974))
- * `GovernorSettings`: a new governor module that manages voting settings updatable through governance actions. ([#2904](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2904))
- * `PaymentSplitter`: now supports ERC20 assets in addition to Ether. ([#2858](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2858))
- * `ECDSA`: add a variant of `toEthSignedMessageHash` for arbitrary length message hashing. ([#2865](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2865))
- * `MerkleProof`: add a `processProof` function that returns the rebuilt root hash given a leaf and a proof. ([#2841](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2841))
- * `VestingWallet`: new contract that handles the vesting of Ether and ERC20 tokens following a customizable vesting schedule. ([#2748](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2748))
- * `Governor`: enable receiving Ether when a Timelock contract is not used. ([#2748](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2849))
- * `GovernorTimelockCompound`: fix ability to use Ether stored in the Timelock contract. ([#2748](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2849))
-
-## 4.3.3
-
- * `ERC1155Supply`: Handle `totalSupply` changes by hooking into `_beforeTokenTransfer` to ensure consistency of balances and supply during `IERC1155Receiver.onERC1155Received` calls.
+- `Ownable`: add an internal `_transferOwnership(address)`. ([#2568](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2568))
+- `AccessControl`: add internal `_grantRole(bytes32,address)` and `_revokeRole(bytes32,address)`. ([#2568](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2568))
+- `AccessControl`: mark `_setupRole(bytes32,address)` as deprecated in favor of `_grantRole(bytes32,address)`. ([#2568](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2568))
+- `AccessControlEnumerable`: hook into `_grantRole(bytes32,address)` and `_revokeRole(bytes32,address)`. ([#2946](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2946))
+- `EIP712`: cache `address(this)` to immutable storage to avoid potential issues if a vanilla contract is used in a delegatecall context. ([#2852](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2852))
+- Add internal `_setApprovalForAll` to `ERC721` and `ERC1155`. ([#2834](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2834))
+- `Governor`: shift vote start and end by one block to better match Compound's GovernorBravo and prevent voting at the Governor level if the voting snapshot is not ready. ([#2892](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2892))
+- `GovernorCompatibilityBravo`: consider quorum an inclusive rather than exclusive minimum to match Compound's GovernorBravo. ([#2974](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2974))
+- `GovernorSettings`: a new governor module that manages voting settings updatable through governance actions. ([#2904](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2904))
+- `PaymentSplitter`: now supports ERC20 assets in addition to Ether. ([#2858](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2858))
+- `ECDSA`: add a variant of `toEthSignedMessageHash` for arbitrary length message hashing. ([#2865](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2865))
+- `MerkleProof`: add a `processProof` function that returns the rebuilt root hash given a leaf and a proof. ([#2841](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2841))
+- `VestingWallet`: new contract that handles the vesting of Ether and ERC20 tokens following a customizable vesting schedule. ([#2748](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2748))
+- `Governor`: enable receiving Ether when a Timelock contract is not used. ([#2849](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2849))
+- `GovernorTimelockCompound`: fix ability to use Ether stored in the Timelock contract. ([#2849](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2849))
+
+## 4.3.3 (2021-11-08)
+
+- `ERC1155Supply`: Handle `totalSupply` changes by hooking into `_beforeTokenTransfer` to ensure consistency of balances and supply during `IERC1155Receiver.onERC1155Received` calls.
 
 ## 4.3.2 (2021-09-14)
 
- * `UUPSUpgradeable`: Add modifiers to prevent `upgradeTo` and `upgradeToAndCall` being executed on any contract that is not the active ERC1967 proxy. This prevents these functions being called on implementation contracts or minimal ERC1167 clones, in particular.
+- `UUPSUpgradeable`: Add modifiers to prevent `upgradeTo` and `upgradeToAndCall` being executed on any contract that is not the active ERC1967 proxy. This prevents these functions being called on implementation contracts or minimal ERC1167 clones, in particular.
 
 ## 4.3.1 (2021-08-26)
 
- * `TimelockController`: Add additional isOperationReady check.
+- `TimelockController`: Add additional isOperationReady check.
 
 ## 4.3.0 (2021-08-17)
 
- * `ERC2771Context`: use private variable from storage to store the forwarder address. Fixes issues where `_msgSender()` was not callable from constructors. ([#2754](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2754))
- * `EnumerableSet`: add `values()` functions that returns an array containing all values in a single call. ([#2768](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2768))
- * `Governor`: added a modular system of `Governor` contracts based on `GovernorAlpha` and `GovernorBravo`. ([#2672](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2672))
- * Add an `interfaces` folder containing solidity interfaces to final ERCs. ([#2517](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2517))
- * `ECDSA`: add `tryRecover` functions that will not throw if the signature is invalid, and will return an error flag instead. ([#2661](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2661))
- * `SignatureChecker`: Reduce gas usage of the `isValidSignatureNow` function for the "signature by EOA" case. ([#2661](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2661))
+- `ERC2771Context`: use private variable from storage to store the forwarder address. Fixes issues where `_msgSender()` was not callable from constructors. ([#2754](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2754))
+- `EnumerableSet`: add `values()` functions that returns an array containing all values in a single call. ([#2768](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2768))
+- `Governor`: added a modular system of `Governor` contracts based on `GovernorAlpha` and `GovernorBravo`. ([#2672](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2672))
+- Add an `interfaces` folder containing solidity interfaces to final ERCs. ([#2517](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2517))
+- `ECDSA`: add `tryRecover` functions that will not throw if the signature is invalid, and will return an error flag instead. ([#2661](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2661))
+- `SignatureChecker`: Reduce gas usage of the `isValidSignatureNow` function for the "signature by EOA" case. ([#2661](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2661))
 
 ## 4.2.0 (2021-06-30)
 
- * `ERC20Votes`: add a new extension of the `ERC20` token with support for voting snapshots and delegation. ([#2632](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2632))
- * `ERC20VotesComp`: Variant of `ERC20Votes` that is compatible with Compound's `Comp` token interface but restricts supply to `uint96`. ([#2706](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2706))
- * `ERC20Wrapper`: add a new extension of the `ERC20` token which wraps an underlying token. Deposit and withdraw guarantee that the total supply is backed by a corresponding amount of underlying token. ([#2633](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2633))
- * Enumerables: Improve gas cost of removal in `EnumerableSet` and `EnumerableMap`.
- * Enumerables: Improve gas cost of lookup in `EnumerableSet` and `EnumerableMap`.
- * `Counter`: add a reset method. ([#2678](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2678))
- * Tokens: Wrap definitely safe subtractions in `unchecked` blocks.
- * `Math`: Add a `ceilDiv` method for performing ceiling division.
- * `ERC1155Supply`: add a new `ERC1155` extension that keeps track of the totalSupply of each tokenId. ([#2593](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2593))
- * `BitMaps`: add a new `BitMaps` library that provides a storage efficient datastructure for `uint256` to `bool` mapping with contiguous keys. ([#2710](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2710))
+- `ERC20Votes`: add a new extension of the `ERC20` token with support for voting snapshots and delegation. ([#2632](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2632))
+- `ERC20VotesComp`: Variant of `ERC20Votes` that is compatible with Compound's `Comp` token interface but restricts supply to `uint96`. ([#2706](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2706))
+- `ERC20Wrapper`: add a new extension of the `ERC20` token which wraps an underlying token. Deposit and withdraw guarantee that the total supply is backed by a corresponding amount of underlying token. ([#2633](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2633))
+- Enumerables: Improve gas cost of removal in `EnumerableSet` and `EnumerableMap`.
+- Enumerables: Improve gas cost of lookup in `EnumerableSet` and `EnumerableMap`.
+- `Counter`: add a reset method. ([#2678](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2678))
+- Tokens: Wrap definitely safe subtractions in `unchecked` blocks.
+- `Math`: Add a `ceilDiv` method for performing ceiling division.
+- `ERC1155Supply`: add a new `ERC1155` extension that keeps track of the totalSupply of each tokenId. ([#2593](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2593))
+- `BitMaps`: add a new `BitMaps` library that provides a storage efficient datastructure for `uint256` to `bool` mapping with contiguous keys. ([#2710](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2710))
 
 ### Breaking Changes
 
- * `ERC20FlashMint` is no longer a Draft ERC. ([#2673](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2673)))
+- `ERC20FlashMint` is no longer a Draft ERC. ([#2673](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2673)))
 
 **How to update:** Change your import paths by removing the `draft-` prefix from `@openzeppelin/contracts/token/ERC20/extensions/draft-ERC20FlashMint.sol`.
 
@@ -244,16 +296,16 @@ It is no longer possible to call an `initializer`-protected function from within
 
 ## 4.1.0 (2021-04-29)
 
- * `IERC20Metadata`: add a new extended interface that includes the optional `name()`, `symbol()` and `decimals()` functions. ([#2561](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2561))
- * `ERC777`: make reception acquirement optional in `_mint`. ([#2552](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2552))
- * `ERC20Permit`: add a `_useNonce` to enable further usage of ERC712 signatures. ([#2565](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2565))
- * `ERC20FlashMint`: add an implementation of the ERC3156 extension for flash-minting ERC20 tokens. ([#2543](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2543))
- * `SignatureChecker`: add a signature verification library that supports both EOA and ERC1271 compliant contracts as signers. ([#2532](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2532))
- * `Multicall`: add abstract contract with `multicall(bytes[] calldata data)` function to bundle multiple calls together ([#2608](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2608))
- * `ECDSA`: add support for ERC2098 short-signatures. ([#2582](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2582))
- * `AccessControl`: add an `onlyRole` modifier to restrict specific function to callers bearing a specific role. ([#2609](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2609))
- * `StorageSlot`: add a library for reading and writing primitive types to specific storage slots. ([#2542](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2542))
- * UUPS Proxies: add `UUPSUpgradeable` to implement the UUPS proxy pattern together with `EIP1967Proxy`. ([#2542](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2542))
+- `IERC20Metadata`: add a new extended interface that includes the optional `name()`, `symbol()` and `decimals()` functions. ([#2561](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2561))
+- `ERC777`: make reception acquirement optional in `_mint`. ([#2552](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2552))
+- `ERC20Permit`: add a `_useNonce` to enable further usage of ERC712 signatures. ([#2565](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2565))
+- `ERC20FlashMint`: add an implementation of the ERC3156 extension for flash-minting ERC20 tokens. ([#2543](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2543))
+- `SignatureChecker`: add a signature verification library that supports both EOA and ERC1271 compliant contracts as signers. ([#2532](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2532))
+- `Multicall`: add abstract contract with `multicall(bytes[] calldata data)` function to bundle multiple calls together ([#2608](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2608))
+- `ECDSA`: add support for ERC2098 short-signatures. ([#2582](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2582))
+- `AccessControl`: add an `onlyRole` modifier to restrict specific function to callers bearing a specific role. ([#2609](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2609))
+- `StorageSlot`: add a library for reading and writing primitive types to specific storage slots. ([#2542](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2542))
+- UUPS Proxies: add `UUPSUpgradeable` to implement the UUPS proxy pattern together with `EIP1967Proxy`. ([#2542](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2542))
 
 ### Breaking changes
 
@@ -270,28 +322,28 @@ This release includes two small breaking changes in `TimelockController`.
 
 ## 4.0.0 (2021-03-23)
 
- * Now targeting the 0.8.x line of Solidity compilers. For 0.6.x (resp 0.7.x) support, use version 3.4.0 (resp 3.4.0-solc-0.7) of OpenZeppelin.
- * `Context`: making `_msgData` return `bytes calldata` instead of `bytes memory` ([#2492](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2492))
- * `ERC20`: removed the `_setDecimals` function and the storage slot associated to decimals. ([#2502](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2502))
- * `Strings`: addition of a `toHexString` function.  ([#2504](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2504))
- * `EnumerableMap`: change implementation to optimize for `key → value` lookups instead of enumeration. ([#2518](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2518))
- * `GSN`: deprecate GSNv1 support in favor of upcoming support for GSNv2. ([#2521](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2521))
- * `ERC165`: remove uses of storage in the base ERC165 implementation. ERC165 based contracts now use storage-less virtual functions. Old behavior remains available in the `ERC165Storage` extension. ([#2505](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2505))
- * `Initializable`: make initializer check stricter during construction. ([#2531](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2531))
- * `ERC721`: remove enumerability of tokens from the base implementation. This feature is now provided separately through the `ERC721Enumerable` extension. ([#2511](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2511))
- * `AccessControl`: removed enumerability by default for a more lightweight contract. It is now opt-in through `AccessControlEnumerable`. ([#2512](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2512))
- * Meta Transactions: add `ERC2771Context` and a `MinimalForwarder` for meta-transactions. ([#2508](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2508))
- * Overall reorganization of the contract folder to improve clarity and discoverability. ([#2503](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2503))
- * `ERC20Capped`: optimize gas usage by enforcing the check directly in `_mint`. ([#2524](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2524))
- * Rename `UpgradeableProxy` to `ERC1967Proxy`. ([#2547](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2547))
- * `ERC777`: optimize the gas costs of the constructor. ([#2551](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2551))
- * `ERC721URIStorage`: add a new extension that implements the `_setTokenURI` behavior as it was available in 3.4.0. ([#2555](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2555))
- * `AccessControl`: added ERC165 interface detection. ([#2562](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2562))
- * `ERC1155`: make `uri` public so overloading function can call it using super. ([#2576](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2576))
+- Now targeting the 0.8.x line of Solidity compilers. For 0.6.x (resp 0.7.x) support, use version 3.4.0 (resp 3.4.0-solc-0.7) of OpenZeppelin.
+- `Context`: making `_msgData` return `bytes calldata` instead of `bytes memory` ([#2492](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2492))
+- `ERC20`: removed the `_setDecimals` function and the storage slot associated to decimals. ([#2502](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2502))
+- `Strings`: addition of a `toHexString` function. ([#2504](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2504))
+- `EnumerableMap`: change implementation to optimize for `key → value` lookups instead of enumeration. ([#2518](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2518))
+- `GSN`: deprecate GSNv1 support in favor of upcoming support for GSNv2. ([#2521](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2521))
+- `ERC165`: remove uses of storage in the base ERC165 implementation. ERC165 based contracts now use storage-less virtual functions. Old behavior remains available in the `ERC165Storage` extension. ([#2505](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2505))
+- `Initializable`: make initializer check stricter during construction. ([#2531](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2531))
+- `ERC721`: remove enumerability of tokens from the base implementation. This feature is now provided separately through the `ERC721Enumerable` extension. ([#2511](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2511))
+- `AccessControl`: removed enumerability by default for a more lightweight contract. It is now opt-in through `AccessControlEnumerable`. ([#2512](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2512))
+- Meta Transactions: add `ERC2771Context` and a `MinimalForwarder` for meta-transactions. ([#2508](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2508))
+- Overall reorganization of the contract folder to improve clarity and discoverability. ([#2503](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2503))
+- `ERC20Capped`: optimize gas usage by enforcing the check directly in `_mint`. ([#2524](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2524))
+- Rename `UpgradeableProxy` to `ERC1967Proxy`. ([#2547](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2547))
+- `ERC777`: optimize the gas costs of the constructor. ([#2551](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2551))
+- `ERC721URIStorage`: add a new extension that implements the `_setTokenURI` behavior as it was available in 3.4.0. ([#2555](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2555))
+- `AccessControl`: added ERC165 interface detection. ([#2562](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2562))
+- `ERC1155`: make `uri` public so overloading function can call it using super. ([#2576](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2576))
 
 ### Bug fixes for beta releases
 
- * `AccessControlEnumerable`: Fixed `renounceRole` not updating enumerable set of addresses for a role. ([#2572](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2572))
+- `AccessControlEnumerable`: Fixed `renounceRole` not updating enumerable set of addresses for a role. ([#2572](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2572))
 
 ### How to upgrade from 3.x
 
@@ -305,56 +357,59 @@ Make sure you're using git or another version control system to be able to recov
 
 ### How to upgrade from 4.0-beta.x
 
-Some further changes have been done between the different beta iterations. Transitions made during this period are configured in the `migrate-imports` script. Consequently, you can upgrade from any previous 4.0-beta.x version using the same script as described in the *How to upgrade from 3.x* section.
+Some further changes have been done between the different beta iterations. Transitions made during this period are configured in the `migrate-imports` script. Consequently, you can upgrade from any previous 4.0-beta.x version using the same script as described in the _How to upgrade from 3.x_ section.
 
-## 3.4.2
+## 3.4.2 (2021-07-24)
 
- * `TimelockController`: Add additional isOperationReady check.
+- `TimelockController`: Add additional isOperationReady check.
 
 ## 3.4.1 (2021-03-03)
 
- * `ERC721`: made `_approve` an internal function (was private).
+- `ERC721`: made `_approve` an internal function (was private).
 
 ## 3.4.0 (2021-02-02)
 
- * `BeaconProxy`: added new kind of proxy that allows simultaneous atomic upgrades. ([#2411](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2411))
- * `EIP712`: added helpers to verify EIP712 typed data signatures on chain. ([#2418](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2418))
- * `ERC20Permit`: added an implementation of the ERC20 permit extension for gasless token approvals. ([#2237](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2237))
- * Presets: added token presets with preminted fixed supply `ERC20PresetFixedSupply` and `ERC777PresetFixedSupply`. ([#2399](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2399))
- * `Address`: added `functionDelegateCall`, similar to the existing `functionCall`. ([#2333](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2333))
- * `Clones`: added a library for deploying EIP 1167 minimal proxies. ([#2449](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2449))
- * `Context`: moved from `contracts/GSN` to `contracts/utils`. ([#2453](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2453))
- * `PaymentSplitter`: replace usage of `.transfer()` with `Address.sendValue` for improved compatibility with smart wallets. ([#2455](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2455))
- * `UpgradeableProxy`: bubble revert reasons from initialization calls. ([#2454](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2454))
- * `SafeMath`: fix a memory allocation issue by adding new `SafeMath.tryOp(uint,uint)→(bool,uint)` functions. `SafeMath.op(uint,uint,string)→uint` are now deprecated. ([#2462](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2462))
- * `EnumerableMap`: fix a memory allocation issue by adding new `EnumerableMap.tryGet(uint)→(bool,address)` functions. `EnumerableMap.get(uint)→string` is now deprecated. ([#2462](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2462))
- * `ERC165Checker`: added batch `getSupportedInterfaces`. ([#2469](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2469))
- * `RefundEscrow`: `beneficiaryWithdraw` will forward all available gas to the beneficiary. ([#2480](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2480))
- * Many view and pure functions have been made virtual to customize them via overrides. In many cases this will not imply that other functions in the contract will automatically adapt to the overridden definitions. People who wish to override should consult the source code to understand the impact and if they need to override any additional functions to achieve the desired behavior.
+- `BeaconProxy`: added new kind of proxy that allows simultaneous atomic upgrades. ([#2411](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2411))
+- `EIP712`: added helpers to verify EIP712 typed data signatures on chain. ([#2418](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2418))
+- `ERC20Permit`: added an implementation of the ERC20 permit extension for gasless token approvals. ([#2237](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2237))
+- Presets: added token presets with preminted fixed supply `ERC20PresetFixedSupply` and `ERC777PresetFixedSupply`. ([#2399](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2399))
+- `Address`: added `functionDelegateCall`, similar to the existing `functionCall`. ([#2333](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2333))
+- `Clones`: added a library for deploying EIP 1167 minimal proxies. ([#2449](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2449))
+- `Context`: moved from `contracts/GSN` to `contracts/utils`. ([#2453](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2453))
+- `PaymentSplitter`: replace usage of `.transfer()` with `Address.sendValue` for improved compatibility with smart wallets. ([#2455](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2455))
+- `UpgradeableProxy`: bubble revert reasons from initialization calls. ([#2454](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2454))
+- `SafeMath`: fix a memory allocation issue by adding new `SafeMath.tryOp(uint,uint)→(bool,uint)` functions. `SafeMath.op(uint,uint,string)→uint` are now deprecated. ([#2462](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2462))
+- `EnumerableMap`: fix a memory allocation issue by adding new `EnumerableMap.tryGet(uint)→(bool,address)` functions. `EnumerableMap.get(uint)→string` is now deprecated. ([#2462](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2462))
+- `ERC165Checker`: added batch `getSupportedInterfaces`. ([#2469](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2469))
+- `RefundEscrow`: `beneficiaryWithdraw` will forward all available gas to the beneficiary. ([#2480](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2480))
+- Many view and pure functions have been made virtual to customize them via overrides. In many cases this will not imply that other functions in the contract will automatically adapt to the overridden definitions. People who wish to override should consult the source code to understand the impact and if they need to override any additional functions to achieve the desired behavior.
 
 ### Security Fixes
 
- * `ERC777`: fix potential reentrancy issues for custom extensions to `ERC777`. ([#2483](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2483))
+- `ERC777`: fix potential reentrancy issues for custom extensions to `ERC777`. ([#2483](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2483))
 
 If you're using our implementation of ERC777 from version 3.3.0 or earlier, and you define a custom `_beforeTokenTransfer` function that writes to a storage variable, you may be vulnerable to a reentrancy attack. If you're affected and would like assistance please write to security@openzeppelin.com. [Read more in the pull request.](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2483)
 
 ## 3.3.0 (2020-11-26)
 
- * Now supports both Solidity 0.6 and 0.7. Compiling with solc 0.7 will result in warnings. Install the `solc-0.7` tag to compile without warnings.
- * `Address`: added `functionStaticCall`, similar to the existing `functionCall`. ([#2333](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2333))
- * `TimelockController`: added a contract to augment access control schemes with a delay. ([#2354](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2354))
- * `EnumerableSet`: added `Bytes32Set`, for sets of `bytes32`. ([#2395](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2395))
+- Now supports both Solidity 0.6 and 0.7. Compiling with solc 0.7 will result in warnings. Install the `solc-0.7` tag to compile without warnings.
+- `Address`: added `functionStaticCall`, similar to the existing `functionCall`. ([#2333](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2333))
+- `TimelockController`: added a contract to augment access control schemes with a delay. ([#2354](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2354))
+- `EnumerableSet`: added `Bytes32Set`, for sets of `bytes32`. ([#2395](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2395))
 
 ## 3.2.2-solc-0.7 (2020-10-28)
- * Resolve warnings introduced by Solidity 0.7.4. ([#2396](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2396))
+
+- Resolve warnings introduced by Solidity 0.7.4. ([#2396](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2396))
 
 ## 3.2.1-solc-0.7 (2020-09-15)
- * `ERC777`: Remove a warning about function state visibility in Solidity 0.7. ([#2327](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2327))
+
+- `ERC777`: Remove a warning about function state visibility in Solidity 0.7. ([#2327](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2327))
 
 ## 3.2.0 (2020-09-10)
 
 ### New features
- * Proxies: added the proxy contracts from OpenZeppelin SDK. ([#2335](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2335))
+
+- Proxies: added the proxy contracts from OpenZeppelin SDK. ([#2335](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2335))
 
 #### Proxy changes with respect to OpenZeppelin SDK
 
@@ -366,10 +421,12 @@ Aside from upgrading them from Solidity 0.5 to 0.6, we've changed a few minor th
 - `UpgradeabilityProxy._setImplementation` and `AdminUpgradeabilityProxy._setAdmin` were made private.
 
 ### Improvements
- * `Address.isContract`: switched from `extcodehash` to `extcodesize` for less gas usage. ([#2311](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2311))
+
+- `Address.isContract`: switched from `extcodehash` to `extcodesize` for less gas usage. ([#2311](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2311))
 
 ### Breaking changes
- * `ERC20Snapshot`: switched to using `_beforeTokenTransfer` hook instead of overriding ERC20 operations. ([#2312](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2312))
+
+- `ERC20Snapshot`: switched to using `_beforeTokenTransfer` hook instead of overriding ERC20 operations. ([#2312](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2312))
 
 This small change in the way we implemented `ERC20Snapshot` may affect users who are combining this contract with
 other ERC20 flavors, since it no longer overrides `_transfer`, `_mint`, and `_burn`. This can result in having to remove Solidity `override(...)` specifiers in derived contracts for these functions, and to instead have to add it for `_beforeTokenTransfer`. See [Using Hooks](https://docs.openzeppelin.com/contracts/3.x/extending-contracts#using-hooks) in the documentation.
@@ -377,119 +434,134 @@ other ERC20 flavors, since it no longer overrides `_transfer`, `_mint`, and `_bu
 ## 3.1.0 (2020-06-23)
 
 ### New features
- * `SafeCast`: added functions to downcast signed integers (e.g. `toInt32`), improving usability of `SignedSafeMath`. ([#2243](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2243))
- * `functionCall`: new helpers that replicate Solidity's function call semantics, reducing the need to rely on `call`. ([#2264](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2264))
- * `ERC1155`: added support for a base implementation, non-standard extensions and a preset contract. ([#2014](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2014), [#2230](https://github.com/OpenZeppelin/openzeppelin-contracts/issues/2230))
+
+- `SafeCast`: added functions to downcast signed integers (e.g. `toInt32`), improving usability of `SignedSafeMath`. ([#2243](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2243))
+- `functionCall`: new helpers that replicate Solidity's function call semantics, reducing the need to rely on `call`. ([#2264](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2264))
+- `ERC1155`: added support for a base implementation, non-standard extensions and a preset contract. ([#2014](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2014), [#2230](https://github.com/OpenZeppelin/openzeppelin-contracts/issues/2230))
 
 ### Improvements
- * `ReentrancyGuard`: reduced overhead of using the `nonReentrant` modifier. ([#2171](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2171))
- * `AccessControl`: added a `RoleAdminChanged` event to `_setAdminRole`. ([#2214](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2214))
- * Made all `public` functions in the token preset contracts `virtual`. ([#2257](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2257))
+
+- `ReentrancyGuard`: reduced overhead of using the `nonReentrant` modifier. ([#2171](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2171))
+- `AccessControl`: added a `RoleAdminChanged` event to `_setAdminRole`. ([#2214](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2214))
+- Made all `public` functions in the token preset contracts `virtual`. ([#2257](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2257))
 
 ### Deprecations
- * `SafeERC20`: deprecated `safeApprove`. ([#2268](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2268))
+
+- `SafeERC20`: deprecated `safeApprove`. ([#2268](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2268))
 
 ## 3.0.2 (2020-06-08)
 
 ### Improvements
- * Added SPX license identifier to all contracts. ([#2235](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2235))
+
+- Added SPX license identifier to all contracts. ([#2235](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2235))
 
 ## 3.0.1 (2020-04-27)
 
 ### Bugfixes
- * `ERC777`: fixed the `_approve` internal function not validating some of their arguments for non-zero addresses. ([#2213](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2213))
+
+- `ERC777`: fixed the `_approve` internal function not validating some of their arguments for non-zero addresses. ([#2213](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2213))
 
 ## 3.0.0 (2020-04-20)
 
 ### New features
- * `AccessControl`: new contract for managing permissions in a system, replacement for `Ownable` and `Roles`. ([#2112](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2112))
- * `SafeCast`: new functions to convert to and from signed and unsigned values: `toUint256` and `toInt256`. ([#2123](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2123))
- * `EnumerableMap`: a new data structure for key-value pairs (like `mapping`) that can be iterated over. ([#2160](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2160))
+
+- `AccessControl`: new contract for managing permissions in a system, replacement for `Ownable` and `Roles`. ([#2112](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2112))
+- `SafeCast`: new functions to convert to and from signed and unsigned values: `toUint256` and `toInt256`. ([#2123](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2123))
+- `EnumerableMap`: a new data structure for key-value pairs (like `mapping`) that can be iterated over. ([#2160](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2160))
 
 ### Breaking changes
- * `ERC721`: `burn(owner, tokenId)` was removed, use `burn(tokenId)` instead. ([#2125](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2125))
- * `ERC721`: `_checkOnERC721Received` was removed. ([#2125](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2125))
- * `ERC721`: `_transferFrom` and `_safeTransferFrom` were renamed to `_transfer` and `_safeTransfer`. ([#2162](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2162))
- * `Ownable`: removed `_transferOwnership`. ([#2162](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2162))
- * `PullPayment`, `Escrow`: `withdrawWithGas` was removed. The old `withdraw` function now forwards all gas. ([#2125](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2125))
- * `Roles` was removed, use `AccessControl` as a replacement. ([#2112](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2112))
- * `ECDSA`: when receiving an invalid signature, `recover` now reverts instead of returning the zero address. ([#2114](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2114))
- * `Create2`: added an `amount` argument to `deploy` for contracts with `payable` constructors. ([#2117](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2117))
- * `Pausable`: moved to the `utils` directory. ([#2122](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2122))
- * `Strings`: moved to the `utils` directory. ([#2122](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2122))
- * `Counters`: moved to the `utils` directory. ([#2122](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2122))
- * `SignedSafeMath`: moved to the `math` directory. ([#2122](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2122))
- * `ERC20Snapshot`: moved to the `token/ERC20` directory. `snapshot` was changed into an `internal` function. ([#2122](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2122))
- * `Ownable`: moved to the `access` directory. ([#2120](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2120))
- * `Ownable`: removed `isOwner`. ([#2120](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2120))
- * `Secondary`: removed from the library, use `Ownable` instead. ([#2120](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2120))
- * `Escrow`, `ConditionalEscrow`, `RefundEscrow`: these now use `Ownable` instead of `Secondary`, their external API changed accordingly. ([#2120](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2120))
- * `ERC20`: removed `_burnFrom`. ([#2119](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2119))
- * `Address`: removed `toPayable`, use `payable(address)` instead. ([#2133](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2133))
- * `ERC777`: `_send`, `_mint` and `_burn` now use the caller as the operator. ([#2134](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2134))
- * `ERC777`: removed `_callsTokensToSend` and `_callTokensReceived`. ([#2134](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2134))
- * `EnumerableSet`: renamed `get` to `at`. ([#2151](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2151))
- * `ERC165Checker`: functions no longer have a leading underscore. ([#2150](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2150))
- * `ERC721Metadata`, `ERC721Enumerable`: these contracts were removed, and their functionality merged into `ERC721`. ([#2160](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2160))
- * `ERC721`: added a constructor for `name` and `symbol`. ([#2160](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2160))
- * `ERC20Detailed`: this contract was removed and its functionality merged into `ERC20`. ([#2161](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2161))
- * `ERC20`: added a constructor for `name` and `symbol`. `decimals` now defaults to 18. ([#2161](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2161))
- * `Strings`: renamed `fromUint256` to `toString` ([#2188](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2188))
+
+- `ERC721`: `burn(owner, tokenId)` was removed, use `burn(tokenId)` instead. ([#2125](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2125))
+- `ERC721`: `_checkOnERC721Received` was removed. ([#2125](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2125))
+- `ERC721`: `_transferFrom` and `_safeTransferFrom` were renamed to `_transfer` and `_safeTransfer`. ([#2162](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2162))
+- `Ownable`: removed `_transferOwnership`. ([#2162](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2162))
+- `PullPayment`, `Escrow`: `withdrawWithGas` was removed. The old `withdraw` function now forwards all gas. ([#2125](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2125))
+- `Roles` was removed, use `AccessControl` as a replacement. ([#2112](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2112))
+- `ECDSA`: when receiving an invalid signature, `recover` now reverts instead of returning the zero address. ([#2114](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2114))
+- `Create2`: added an `amount` argument to `deploy` for contracts with `payable` constructors. ([#2117](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2117))
+- `Pausable`: moved to the `utils` directory. ([#2122](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2122))
+- `Strings`: moved to the `utils` directory. ([#2122](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2122))
+- `Counters`: moved to the `utils` directory. ([#2122](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2122))
+- `SignedSafeMath`: moved to the `math` directory. ([#2122](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2122))
+- `ERC20Snapshot`: moved to the `token/ERC20` directory. `snapshot` was changed into an `internal` function. ([#2122](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2122))
+- `Ownable`: moved to the `access` directory. ([#2120](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2120))
+- `Ownable`: removed `isOwner`. ([#2120](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2120))
+- `Secondary`: removed from the library, use `Ownable` instead. ([#2120](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2120))
+- `Escrow`, `ConditionalEscrow`, `RefundEscrow`: these now use `Ownable` instead of `Secondary`, their external API changed accordingly. ([#2120](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2120))
+- `ERC20`: removed `_burnFrom`. ([#2119](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2119))
+- `Address`: removed `toPayable`, use `payable(address)` instead. ([#2133](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2133))
+- `ERC777`: `_send`, `_mint` and `_burn` now use the caller as the operator. ([#2134](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2134))
+- `ERC777`: removed `_callsTokensToSend` and `_callTokensReceived`. ([#2134](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2134))
+- `EnumerableSet`: renamed `get` to `at`. ([#2151](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2151))
+- `ERC165Checker`: functions no longer have a leading underscore. ([#2150](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2150))
+- `ERC721Metadata`, `ERC721Enumerable`: these contracts were removed, and their functionality merged into `ERC721`. ([#2160](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2160))
+- `ERC721`: added a constructor for `name` and `symbol`. ([#2160](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2160))
+- `ERC20Detailed`: this contract was removed and its functionality merged into `ERC20`. ([#2161](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2161))
+- `ERC20`: added a constructor for `name` and `symbol`. `decimals` now defaults to 18. ([#2161](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2161))
+- `Strings`: renamed `fromUint256` to `toString` ([#2188](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2188))
 
 ## 2.5.1 (2020-04-24)
 
 ### Bugfixes
- * `ERC777`: fixed the `_send` and `_approve` internal functions not validating some of their arguments for non-zero addresses. ([#2212](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2212))
+
+- `ERC777`: fixed the `_send` and `_approve` internal functions not validating some of their arguments for non-zero addresses. ([#2212](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2212))
 
 ## 2.5.0 (2020-02-04)
 
 ### New features
- * `SafeCast.toUintXX`: new library for integer downcasting, which allows for safe operation on smaller types (e.g. `uint32`) when combined with `SafeMath`. ([#1926](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1926))
- * `ERC721Metadata`: added `baseURI`, which can be used for dramatic gas savings when all token URIs share a prefix (e.g. `http://api.myapp.com/tokens/<id>`). ([#1970](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1970))
- * `EnumerableSet`: new library for storing enumerable sets of values. Only `AddressSet` is supported in this release. ([#2061](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/2061))
- * `Create2`: simple library to make usage of the `CREATE2` opcode easier. ([#1744](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/1744))
+
+- `SafeCast.toUintXX`: new library for integer downcasting, which allows for safe operation on smaller types (e.g. `uint32`) when combined with `SafeMath`. ([#1926](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1926))
+- `ERC721Metadata`: added `baseURI`, which can be used for dramatic gas savings when all token URIs share a prefix (e.g. `http://api.myapp.com/tokens/<id>`). ([#1970](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1970))
+- `EnumerableSet`: new library for storing enumerable sets of values. Only `AddressSet` is supported in this release. ([#2061](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/2061))
+- `Create2`: simple library to make usage of the `CREATE2` opcode easier. ([#1744](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/1744))
 
 ### Improvements
- * `ERC777`: `_burn` is now internal, providing more flexibility and making it easier to create tokens that deflate. ([#1908](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/1908))
- * `ReentrancyGuard`: greatly improved gas efficiency by using the net gas metering mechanism introduced in the Istanbul hardfork. ([#1992](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/1992), [#1996](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/1996))
- * `ERC777`: improve extensibility by making `_send` and related functions `internal`. ([#2027](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2027))
- * `ERC721`: improved revert reason when transferring tokens to a non-recipient contract. ([#2018](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2018))
+
+- `ERC777`: `_burn` is now internal, providing more flexibility and making it easier to create tokens that deflate. ([#1908](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/1908))
+- `ReentrancyGuard`: greatly improved gas efficiency by using the net gas metering mechanism introduced in the Istanbul hardfork. ([#1992](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/1992), [#1996](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/1996))
+- `ERC777`: improve extensibility by making `_send` and related functions `internal`. ([#2027](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2027))
+- `ERC721`: improved revert reason when transferring tokens to a non-recipient contract. ([#2018](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2018))
 
 ### Breaking changes
- * `ERC165Checker` now requires a minimum Solidity compiler version of 0.5.10. ([#1829](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1829))
+
+- `ERC165Checker` now requires a minimum Solidity compiler version of 0.5.10. ([#1829](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1829))
 
 ## 2.4.0 (2019-10-29)
 
 ### New features
- * `Address.toPayable`: added a helper to convert between address types without having to resort to low-level casting. ([#1773](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1773))
- * Facilities to make metatransaction-enabled contracts through the Gas Station Network. ([#1844](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/1844))
- * `Address.sendValue`: added a replacement to Solidity's `transfer`, removing the fixed gas stipend. ([#1962](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1962))
- * Added replacement for functions that don't forward all gas (which have been deprecated): ([#1976](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1976))
-   * `PullPayment.withdrawPaymentsWithGas(address payable payee)`
-   * `Escrow.withdrawWithGas(address payable payee)`
- * `SafeMath`: added support for custom error messages to `sub`, `div` and `mod` functions. ([#1828](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/1828))
+
+- `Address.toPayable`: added a helper to convert between address types without having to resort to low-level casting. ([#1773](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1773))
+- Facilities to make metatransaction-enabled contracts through the Gas Station Network. ([#1844](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/1844))
+- `Address.sendValue`: added a replacement to Solidity's `transfer`, removing the fixed gas stipend. ([#1962](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1962))
+- Added replacement for functions that don't forward all gas (which have been deprecated): ([#1976](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1976))
+  - `PullPayment.withdrawPaymentsWithGas(address payable payee)`
+  - `Escrow.withdrawWithGas(address payable payee)`
+- `SafeMath`: added support for custom error messages to `sub`, `div` and `mod` functions. ([#1828](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/1828))
 
 ### Improvements
- * `Address.isContract`: switched from `extcodesize` to `extcodehash` for less gas usage. ([#1802](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1802))
- * `ERC20` and `ERC777` updated to throw custom errors on subtraction overflows. ([#1828](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/1828))
+
+- `Address.isContract`: switched from `extcodesize` to `extcodehash` for less gas usage. ([#1802](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1802))
+- `ERC20` and `ERC777` updated to throw custom errors on subtraction overflows. ([#1828](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/1828))
 
 ### Deprecations
- * Deprecated functions that don't forward all gas: ([#1976](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1976))
-   * `PullPayment.withdrawPayments(address payable payee)`
-   * `Escrow.withdraw(address payable payee)`
+
+- Deprecated functions that don't forward all gas: ([#1976](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1976))
+  - `PullPayment.withdrawPayments(address payable payee)`
+  - `Escrow.withdraw(address payable payee)`
 
 ### Breaking changes
- * `Address` now requires a minimum Solidity compiler version of 0.5.5. ([#1802](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1802))
- * `SignatureBouncer` has been removed from drafts, both to avoid confusions with the GSN and `GSNRecipientSignature` (previously called `GSNBouncerSignature`) and because the API was not very clear. ([#1879](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/1879))
+
+- `Address` now requires a minimum Solidity compiler version of 0.5.5. ([#1802](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1802))
+- `SignatureBouncer` has been removed from drafts, both to avoid confusions with the GSN and `GSNRecipientSignature` (previously called `GSNBouncerSignature`) and because the API was not very clear. ([#1879](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/1879))
 
 ### How to upgrade from 2.4.0-beta
 
 The final 2.4.0 release includes a refactor of the GSN contracts that will be a breaking change for 2.4.0-beta users.
 
- * The default empty implementations of `_preRelayedCall` and `_postRelayedCall` were removed and must now be explicitly implemented always in custom recipients. If your custom recipient didn't include an implementation, you can provide an empty one.
- * `GSNRecipient`, `GSNBouncerBase`, and `GSNContext` were all merged into `GSNRecipient`.
- * `GSNBouncerSignature` and `GSNBouncerERC20Fee` were renamed to `GSNRecipientSignature` and `GSNRecipientERC20Fee`.
- * It is no longer necessary to inherit from `GSNRecipient` when using `GSNRecipientSignature` and `GSNRecipientERC20Fee`.
+- The default empty implementations of `_preRelayedCall` and `_postRelayedCall` were removed and must now be explicitly implemented always in custom recipients. If your custom recipient didn't include an implementation, you can provide an empty one.
+- `GSNRecipient`, `GSNBouncerBase`, and `GSNContext` were all merged into `GSNRecipient`.
+- `GSNBouncerSignature` and `GSNBouncerERC20Fee` were renamed to `GSNRecipientSignature` and `GSNRecipientERC20Fee`.
+- It is no longer necessary to inherit from `GSNRecipient` when using `GSNRecipientSignature` and `GSNRecipientERC20Fee`.
 
 For example, a contract using `GSNBouncerSignature` would have to be changed in the following way.
 
@@ -500,81 +572,94 @@ For example, a contract using `GSNBouncerSignature` would have to be changed in
 
 Refer to the table below to adjust your inheritance list.
 
-| 2.4.0-beta                         | 2.4.0                        |
-| ---------------------------------- | ---------------------------- |
-| `GSNRecipient, GSNBouncerSignature`| `GSNRecipientSignature`      |
-| `GSNRecipient, GSNBouncerERC20Fee` | `GSNRecipientERC20Fee`       |
-| `GSNBouncerBase`                   | `GSNRecipient`               |
+| 2.4.0-beta                          | 2.4.0                   |
+| ----------------------------------- | ----------------------- |
+| `GSNRecipient, GSNBouncerSignature` | `GSNRecipientSignature` |
+| `GSNRecipient, GSNBouncerERC20Fee`  | `GSNRecipientERC20Fee`  |
+| `GSNBouncerBase`                    | `GSNRecipient`          |
 
 ## 2.3.0 (2019-05-27)
 
 ### New features
- * `ERC1820`: added support for interacting with the [ERC1820](https://eips.ethereum.org/EIPS/eip-1820) registry contract (`IERC1820Registry`), as well as base contracts that can be registered as implementers there. ([#1677](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1677))
- * `ERC777`: support for the [ERC777 token](https://eips.ethereum.org/EIPS/eip-777), which has multiple improvements over `ERC20` (but is backwards compatible with it) such as built-in burning, a more  straightforward permission system, and optional sender and receiver hooks on transfer (mandatory for contracts!). ([#1684](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1684))
- * All contracts now have revert reason strings, which give insight into error conditions, and help debug failing transactions. ([#1704](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1704))
+
+- `ERC1820`: added support for interacting with the [ERC1820](https://eips.ethereum.org/EIPS/eip-1820) registry contract (`IERC1820Registry`), as well as base contracts that can be registered as implementers there. ([#1677](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1677))
+- `ERC777`: support for the [ERC777 token](https://eips.ethereum.org/EIPS/eip-777), which has multiple improvements over `ERC20` (but is backwards compatible with it) such as built-in burning, a more straightforward permission system, and optional sender and receiver hooks on transfer (mandatory for contracts!). ([#1684](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1684))
+- All contracts now have revert reason strings, which give insight into error conditions, and help debug failing transactions. ([#1704](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1704))
 
 ### Improvements
- * Reverted the Solidity version bump done in v2.2.0, setting the minimum compiler version to v0.5.0, to prevent unexpected build breakage. Users are encouraged however to stay on top of new compiler releases, which usually include bugfixes. ([#1729](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1729))
+
+- Reverted the Solidity version bump done in v2.2.0, setting the minimum compiler version to v0.5.0, to prevent unexpected build breakage. Users are encouraged however to stay on top of new compiler releases, which usually include bugfixes. ([#1729](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1729))
 
 ### Bugfixes
- * `PostDeliveryCrowdsale`: some validations where skipped when paired with other crowdsale flavors, such as `AllowanceCrowdsale`, or `MintableCrowdsale` and `ERC20Capped`, which could cause buyers to not be able to claim their purchased tokens. ([#1721](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1721))
- * `ERC20._transfer`: the `from` argument was allowed to be the zero address, so it was possible to internally trigger a transfer of 0 tokens from the zero address. This address is not a valid destinatary of transfers, nor can it give or receive allowance, so this behavior was inconsistent. It now reverts. ([#1752](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1752))
+
+- `PostDeliveryCrowdsale`: some validations where skipped when paired with other crowdsale flavors, such as `AllowanceCrowdsale`, or `MintableCrowdsale` and `ERC20Capped`, which could cause buyers to not be able to claim their purchased tokens. ([#1721](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1721))
+- `ERC20._transfer`: the `from` argument was allowed to be the zero address, so it was possible to internally trigger a transfer of 0 tokens from the zero address. This address is not a valid destinatary of transfers, nor can it give or receive allowance, so this behavior was inconsistent. It now reverts. ([#1752](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1752))
 
 ## 2.2.0 (2019-03-14)
 
 ### New features
- * `ERC20Snapshot`: create snapshots on demand of the token balances and total supply, to later retrieve and e.g. calculate dividends at a past time. ([#1617](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1617))
- * `SafeERC20`: `ERC20` contracts with no return value (i.e. that revert on failure) are now supported. ([#1655](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1655))
- * `ERC20`: added internal `_approve(address owner, address spender, uint256 value)`, allowing derived contracts to set the allowance of arbitrary accounts. ([#1609](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1609))
- * `ERC20Metadata`: added internal `_setTokenURI(string memory tokenURI)`. ([#1618](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1618))
- * `TimedCrowdsale`: added internal `_extendTime(uint256 newClosingTime)` as well as `TimedCrowdsaleExtended(uint256 prevClosingTime, uint256 newClosingTime)` event allowing to extend the crowdsale, as long as it hasn't already closed.
+
+- `ERC20Snapshot`: create snapshots on demand of the token balances and total supply, to later retrieve and e.g. calculate dividends at a past time. ([#1617](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1617))
+- `SafeERC20`: `ERC20` contracts with no return value (i.e. that revert on failure) are now supported. ([#1655](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1655))
+- `ERC20`: added internal `_approve(address owner, address spender, uint256 value)`, allowing derived contracts to set the allowance of arbitrary accounts. ([#1609](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1609))
+- `ERC20Metadata`: added internal `_setTokenURI(string memory tokenURI)`. ([#1618](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1618))
+- `TimedCrowdsale`: added internal `_extendTime(uint256 newClosingTime)` as well as `TimedCrowdsaleExtended(uint256 prevClosingTime, uint256 newClosingTime)` event allowing to extend the crowdsale, as long as it hasn't already closed.
 
 ### Improvements
- * Upgraded the minimum compiler version to v0.5.2: this removes many Solidity warnings that were false positives. ([#1606](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1606))
- * `ECDSA`: `recover` no longer accepts malleable signatures (those using upper-range values for `s`, or 0/1 for `v`). ([#1622](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1622))
- * ``ERC721``'s transfers are now more gas efficient due to removal of unnecessary `SafeMath` calls. ([#1610](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1610))
- * Fixed variable shadowing issues. ([#1606](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1606))
+
+- Upgraded the minimum compiler version to v0.5.2: this removes many Solidity warnings that were false positives. ([#1606](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1606))
+- `ECDSA`: `recover` no longer accepts malleable signatures (those using upper-range values for `s`, or 0/1 for `v`). ([#1622](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1622))
+- `ERC721`'s transfers are now more gas efficient due to removal of unnecessary `SafeMath` calls. ([#1610](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1610))
+- Fixed variable shadowing issues. ([#1606](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1606))
 
 ### Bugfixes
- * (minor) `SafeERC20`: `safeApprove` wasn't properly checking for a zero allowance when attempting to set a non-zero allowance. ([#1647](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1647))
+
+- (minor) `SafeERC20`: `safeApprove` wasn't properly checking for a zero allowance when attempting to set a non-zero allowance. ([#1647](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1647))
 
 ### Breaking changes in drafts
- * `TokenMetadata` has been renamed to `ERC20Metadata`. ([#1618](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1618))
- * The library `Counter` has been renamed to `Counters` and its API has been improved. See an example in `ERC721`, lines [17](https://github.com/OpenZeppelin/openzeppelin-solidity/blob/3cb4a00fce1da76196ac0ac3a0ae9702b99642b5/contracts/token/ERC721/ERC721.sol#L17) and [204](https://github.com/OpenZeppelin/openzeppelin-solidity/blob/3cb4a00fce1da76196ac0ac3a0ae9702b99642b5/contracts/token/ERC721/ERC721.sol#L204). ([#1610](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1610))
+
+- `TokenMetadata` has been renamed to `ERC20Metadata`. ([#1618](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1618))
+- The library `Counter` has been renamed to `Counters` and its API has been improved. See an example in `ERC721`, lines [17](https://github.com/OpenZeppelin/openzeppelin-solidity/blob/3cb4a00fce1da76196ac0ac3a0ae9702b99642b5/contracts/token/ERC721/ERC721.sol#L17) and [204](https://github.com/OpenZeppelin/openzeppelin-solidity/blob/3cb4a00fce1da76196ac0ac3a0ae9702b99642b5/contracts/token/ERC721/ERC721.sol#L204). ([#1610](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1610))
 
 ## 2.1.3 (2019-02-26)
- * Backported `SafeERC20.safeApprove` bugfix. ([#1647](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1647))
+
+- Backported `SafeERC20.safeApprove` bugfix. ([#1647](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1647))
 
 ## 2.1.2 (2019-01-17)
- * Removed most of the test suite from the npm package, except `PublicRole.behavior.js`, which may be useful to users testing their own `Roles`.
+
+- Removed most of the test suite from the npm package, except `PublicRole.behavior.js`, which may be useful to users testing their own `Roles`.
 
 ## 2.1.1 (2019-01-04)
- * Version bump to avoid conflict in the npm registry.
+
+- Version bump to avoid conflict in the npm registry.
 
 ## 2.1.0 (2019-01-04)
 
 ### New features
- * Now targeting the 0.5.x line of Solidity compilers. For 0.4.24 support, use version 2.0 of OpenZeppelin.
- * `WhitelistCrowdsale`: a crowdsale where only whitelisted accounts (`WhitelistedRole`) can purchase tokens. Adding or removing accounts from the whitelist is done by whitelist admins (`WhitelistAdminRole`). Similar to the pre-2.0 `WhitelistedCrowdsale`. ([#1525](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1525), [#1589](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1589))
- * `RefundablePostDeliveryCrowdsale`: replacement for `RefundableCrowdsale` (deprecated, see below) where tokens are only granted once the crowdsale ends (if it meets its goal). ([#1543](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1543))
- * `PausableCrowdsale`: allows for pausers (`PauserRole`) to pause token purchases. Other crowdsale operations (e.g. withdrawals and refunds, if applicable) are not affected. ([#832](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/832))
- * `ERC20`: `transferFrom` and `_burnFrom ` now emit `Approval` events, to represent the token's state comprehensively through events. ([#1524](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1524))
- * `ERC721`: added `_burn(uint256 tokenId)`, replacing the similar deprecated function (see below). ([#1550](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1550))
- * `ERC721`: added `_tokensOfOwner(address owner)`, allowing to internally retrieve the array of an account's owned tokens. ([#1522](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1522))
- * Crowdsales: all constructors are now `public`, meaning it is not necessary to extend these contracts in order to deploy them. The exception is `FinalizableCrowdsale`, since it is meaningless unless extended. ([#1564](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1564))
- * `SignedSafeMath`: added overflow-safe operations for signed integers (`int256`). ([#1559](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1559), [#1588](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1588))
+
+- Now targeting the 0.5.x line of Solidity compilers. For 0.4.24 support, use version 2.0 of OpenZeppelin.
+- `WhitelistCrowdsale`: a crowdsale where only whitelisted accounts (`WhitelistedRole`) can purchase tokens. Adding or removing accounts from the whitelist is done by whitelist admins (`WhitelistAdminRole`). Similar to the pre-2.0 `WhitelistedCrowdsale`. ([#1525](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1525), [#1589](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1589))
+- `RefundablePostDeliveryCrowdsale`: replacement for `RefundableCrowdsale` (deprecated, see below) where tokens are only granted once the crowdsale ends (if it meets its goal). ([#1543](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1543))
+- `PausableCrowdsale`: allows for pausers (`PauserRole`) to pause token purchases. Other crowdsale operations (e.g. withdrawals and refunds, if applicable) are not affected. ([#832](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/832))
+- `ERC20`: `transferFrom` and `_burnFrom ` now emit `Approval` events, to represent the token's state comprehensively through events. ([#1524](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1524))
+- `ERC721`: added `_burn(uint256 tokenId)`, replacing the similar deprecated function (see below). ([#1550](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1550))
+- `ERC721`: added `_tokensOfOwner(address owner)`, allowing to internally retrieve the array of an account's owned tokens. ([#1522](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1522))
+- Crowdsales: all constructors are now `public`, meaning it is not necessary to extend these contracts in order to deploy them. The exception is `FinalizableCrowdsale`, since it is meaningless unless extended. ([#1564](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1564))
+- `SignedSafeMath`: added overflow-safe operations for signed integers (`int256`). ([#1559](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1559), [#1588](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1588))
 
 ### Improvements
- * The compiler version required by `Array` was behind the rest of the library so it was updated to `v0.4.24`. ([#1553](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1553))
- * Now conforming to a 4-space indentation code style. ([1508](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1508))
- * `ERC20`: more gas efficient due to removed redundant `require`s. ([#1409](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1409))
- * `ERC721`: fixed a bug that prevented internal data structures from being properly cleaned, missing potential gas refunds. ([#1539](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1539) and [#1549](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1549))
- * `ERC721`: general gas savings on `transferFrom`, `_mint` and `_burn`, due to redundant `require`s and `SSTORE`s. ([#1549](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1549))
+
+- The compiler version required by `Array` was behind the rest of the library so it was updated to `v0.4.24`. ([#1553](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1553))
+- Now conforming to a 4-space indentation code style. ([1508](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1508))
+- `ERC20`: more gas efficient due to removed redundant `require`s. ([#1409](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1409))
+- `ERC721`: fixed a bug that prevented internal data structures from being properly cleaned, missing potential gas refunds. ([#1539](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1539) and [#1549](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1549))
+- `ERC721`: general gas savings on `transferFrom`, `_mint` and `_burn`, due to redundant `require`s and `SSTORE`s. ([#1549](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1549))
 
 ### Bugfixes
 
 ### Breaking changes
 
 ### Deprecations
- * `ERC721._burn(address owner, uint256 tokenId)`: due to the `owner` parameter being unnecessary. ([#1550](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1550))
- * `RefundableCrowdsale`: due to trading abuse potential on crowdsales that miss their goal. ([#1543](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1543))
+
+- `ERC721._burn(address owner, uint256 tokenId)`: due to the `owner` parameter being unnecessary. ([#1550](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1550))
+- `RefundableCrowdsale`: due to trading abuse potential on crowdsales that miss their goal. ([#1543](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1543))

CODE_OF_CONDUCT.md

@@ -55,7 +55,7 @@ further defined and clarified by project maintainers.
 ## Enforcement
 
 Instances of abusive, harassing, or otherwise unacceptable behavior may be
-reported by contacting the project team at maintainers@openzeppelin.org. All
+reported by contacting the project team at contact@openzeppelin.com. All
 complaints will be reviewed and investigated and will result in a response that
 is deemed necessary and appropriate to the circumstances. The project team is
 obligated to maintain confidentiality with regard to the reporter of an incident.

CONTRIBUTING.md

@@ -1,64 +1,36 @@
-Contributing to OpenZeppelin Contracts
-=======
+# Contributing Guidelines
 
-We really appreciate and value contributions to OpenZeppelin Contracts. Please take 5' to review the items listed below to make sure that your contributions are merged as soon as possible.
+There are many ways to contribute to OpenZeppelin Contracts.
 
-## Contribution guidelines
+## Troubleshooting
 
-Smart contracts manage value and are highly vulnerable to errors and attacks. We have very strict [guidelines], please make sure to review them!
+You can help other users in the community to solve their smart contract issues in the [OpenZeppelin Forum].
 
-## Creating Pull Requests (PRs)
+[OpenZeppelin Forum]: https://forum.openzeppelin.com/
 
-As a contributor, you are expected to fork this repository, work on your own fork and then submit pull requests. The pull requests will be reviewed and eventually merged into the main repo. See ["Fork-a-Repo"](https://help.github.com/articles/fork-a-repo/) for how this works.
+## Opening an issue
 
-## A typical workflow
+You can [open an issue] to suggest a feature or report a minor bug. For serious bugs please do not open an issue, instead refer to our [security policy] for appropriate steps.
 
-1) Make sure your fork is up to date with the main repository:
+If you believe your issue may be due to user error and not a problem in the library, consider instead posting a question on the [OpenZeppelin Forum].
 
-```
-cd openzeppelin-contracts
-git remote add upstream https://github.com/OpenZeppelin/openzeppelin-contracts.git
-git fetch upstream
-git pull --rebase upstream master
-```
-NOTE: The directory `openzeppelin-contracts` represents your fork's local copy.
+Before opening an issue, be sure to search through the existing open and closed issues, and consider posting a comment in one of those instead.
 
-2) Branch out from `master` into `fix/some-bug-#123`:
-(Postfixing #123 will associate your PR with the issue #123 and make everyone's life easier =D)
-```
-git checkout -b fix/some-bug-#123
-```
+When requesting a new feature, include as many details as you can, especially around the use cases that motivate it. Features are prioritized according to the impact they may have on the ecosystem, so we appreciate information showing that the impact could be high.
 
-3) Make your changes, add your files, commit, and push to your fork.
+[security policy]: https://github.com/OpenZeppelin/openzeppelin-contracts/security
+[open an issue]: https://github.com/OpenZeppelin/openzeppelin-contracts/issues/new/choose
 
-```
-git add SomeFile.js
-git commit "Fix some bug #123"
-git push origin fix/some-bug-#123
-```
+## Submitting a pull request
 
-4) Run tests, linter, etc. This can be done by running local continuous integration and make sure it passes.
+If you would like to contribute code or documentation you may do so by forking the repository and submitting a pull request.
 
-```bash
-npm test
-npm run lint
-```
+Any non-trivial code contribution must be first discussed with the maintainers in an issue (see [Opening an issue](#opening-an-issue)). Only very minor changes are accepted without prior discussion.
 
-5) Go to [github.com/OpenZeppelin/openzeppelin-contracts](https://github.com/OpenZeppelin/openzeppelin-contracts) in your web browser and issue a new pull request.
+Make sure to read and follow the [engineering guidelines](./GUIDELINES.md). Run linter and tests to make sure your pull request is good before submitting it.
 
-*IMPORTANT* Read the PR template very carefully and make sure to follow all the instructions. These instructions
-refer to some very important conditions that your PR must meet in order to be accepted, such as making sure that all tests pass, JS linting tests pass, Solidity linting tests pass, etc.
+Changelog entries should be added to each pull request by using [Changesets](https://github.com/changesets/changesets/).
 
-6) Maintainers will review your code and possibly ask for changes before your code is pulled in to the main repository. We'll check that all tests pass, review the coding style, and check for general code correctness. If everything is OK, we'll merge your pull request and your code will be part of OpenZeppelin Contracts.
+When opening the pull request you will be presented with a template and a series of instructions. Read through it carefully and follow all the steps. Expect a review and feedback from the maintainers afterwards.
 
-*IMPORTANT* Please pay attention to the maintainer's feedback, since it's a necessary step to keep up with the standards OpenZeppelin Contracts attains to.
-
-## All set!
-
-If you have any questions, feel free to post them to github.com/OpenZeppelin/openzeppelin-contracts/issues.
-
-Finally, if you're looking to collaborate and want to find easy tasks to start, look at the issues we marked as ["Good first issue"](https://github.com/OpenZeppelin/openzeppelin-contracts/labels/good%20first%20issue).
-
-Thanks for your time and code!
-
-[guidelines]: GUIDELINES.md
+If you're looking for a good place to start, look for issues labelled ["good first issue"](https://github.com/OpenZeppelin/openzeppelin-contracts/labels/good%20first%20issue)!

GUIDELINES.md

@@ -1,105 +1,117 @@
-Design Guidelines
-=======
+# Engineering Guidelines
 
-These are some global design goals in OpenZeppelin Contracts.
+## Testing
 
-#### D0 - Security in Depth
-We strive to provide secure, tested, audited code. To achieve this, we need to match intention with function. Thus, documentation, code clarity, community review and security discussions are fundamental.
+Code must be thoroughly tested with quality unit tests.
 
-#### D1 - Simple and Modular
-Simpler code means easier audits, and better understanding of what each component does. We look for small files, small contracts, and small functions. If you can separate a contract into two independent functionalities you should probably do it.
+We defer to the [Moloch Testing Guide](https://github.com/MolochVentures/moloch/tree/master/test#readme) for specific recommendations, though not all of it is relevant here. Note the introduction:
 
-#### D2 - Naming Matters
+> Tests should be written, not only to verify correctness of the target code, but to be comprehensively reviewed by other programmers. Therefore, for mission critical Solidity code, the quality of the tests are just as important (if not more so) than the code itself, and should be written with the highest standards of clarity and elegance.
 
-We take our time with picking names. Code is going to be written once, and read hundreds of times. Renaming for clarity is encouraged.
+Every addition or change to the code must come with relevant and comprehensive tests.
 
-#### D3 - Tests
+Refactors should avoid simultaneous changes to tests.
 
-Write tests for all your code. We encourage Test Driven Development so we know when our code is right. Even though not all code in the repository is tested at the moment, we aim to test every line of code in the future.
+Flaky tests are not acceptable.
 
-#### D4 - Check preconditions and post-conditions
+The test suite should run automatically for every change in the repository, and in pull requests tests must pass before merging.
 
-A very important way to prevent vulnerabilities is to catch a contract’s inconsistent state as early as possible. This is why we want functions to check pre- and post-conditions for executing its logic. When writing code, ask yourself what you are expecting to be true before and after the function runs, and express it in code.
+The test suite coverage must be kept as close to 100% as possible, enforced in pull requests.
 
-#### D5 - Code Consistency
+In some cases unit tests may be insufficient and complementary techniques should be used:
 
-Consistency on the way classes are used is paramount to an easier understanding of the library. The codebase should be as unified as possible. Read existing code and get inspired before you write your own. Follow the style guidelines. Don’t hesitate to ask for help on how to best write a specific piece of code.
+1. Property-based tests (aka. fuzzing) for math-heavy code.
+2. Formal verification for state machines.
 
-#### D6 - Regular Audits
-Following good programming practices is a way to reduce the risk of vulnerabilities, but professional code audits are still needed. We will perform regular code audits on major releases, and hire security professionals to provide independent review.
+## Code style
 
-# Style Guidelines
+Solidity code should be written in a consistent format enforced by a linter, following the official [Solidity Style Guide](https://docs.soliditylang.org/en/latest/style-guide.html). See below for further [Solidity Conventions](#solidity-conventions).
 
-The design guidelines have quite a high abstraction level. These style guidelines are more concrete and easier to apply, and also more opinionated. We value clean code and consistency, and those are prerequisites for us to include new code in the repository. Before proposing a change, please read these guidelines and take some time to familiarize yourself with the style of the existing codebase.
+The code should be simple and straightforward, prioritizing readability and understandability. Consistency and predictability should be maintained across the codebase. In particular, this applies to naming, which should be systematic, clear, and concise.
 
-## Solidity code
+Sometimes these guidelines may be broken if doing so brings significant efficiency gains, but explanatory comments should be added.
 
-In order to be consistent with all the other Solidity projects, we follow the
-[official recommendations documented in the Solidity style guide](http://solidity.readthedocs.io/en/latest/style-guide.html).
+Modularity should be pursued, but not at the cost of the above priorities.
 
-Any exception or additions specific to our project are documented below.
+## Documentation
 
-* Try to avoid acronyms and abbreviations.
+For contributors, project guidelines and processes must be documented publicly.
 
-* All state variables should be private.
+For users, features must be abundantly documented. Documentation should include answers to common questions, solutions to common problems, and recommendations for critical decisions that the user may face.
 
-* Private state variables should have an underscore prefix.
+All changes to the core codebase (excluding tests, auxiliary scripts, etc.) must be documented in a changelog, except for purely cosmetic or documentation changes.
 
-    ```
-    contract TestContract {
-      uint256 private _privateVar;
-      uint256 internal _internalVar;
-    }
-    ```
+## Peer review
+
+All changes must be submitted through pull requests and go through peer code review.
+
+The review must be approached by the reviewer in a similar way as if it was an audit of the code in question (but importantly it is not a substitute for and should not be considered an audit).
+
+Reviewers should enforce code and project guidelines.
+
+External contributions must be reviewed separately by multiple maintainers.
+
+## Automation
+
+Automation should be used as much as possible to reduce the possibility of human error and forgetfulness.
+
+Automations that make use of sensitive credentials must use secure secret management, and must be strengthened against attacks such as [those on GitHub Actions worklows](https://github.com/nikitastupin/pwnhub).
+
+Some other examples of automation are:
+
+- Looking for common security vulnerabilities or errors in our code (eg. reentrancy analysis).
+- Keeping dependencies up to date and monitoring for vulnerable dependencies.
+
+## Pull requests
+
+Pull requests are squash-merged to keep the `master` branch history clean. The title of the pull request becomes the commit message, so it should be written in a consistent format:
 
-* Parameters must not be prefixed with an underscore.
+1) Begin with a capital letter.
+2) Do not end with a period.
+3) Write in the imperative: "Add feature X" and not "Adds feature X" or "Added feature X".
 
-    ```
-    function test(uint256 testParameter1, uint256 testParameter2) {
-    ...
-    }
-    ```
+This repository does not follow conventional commits, so do not prefix the title with "fix:" or "feat:".
 
-* Internal and private functions should have an underscore prefix.
+Work in progress pull requests should be submitted as Drafts and should not be prefixed with "WIP:".
 
-    ```
-    function _testInternal() internal {
-      ...
-    }
-    ```
+Branch names don't matter, and commit messages within a pull request mostly don't matter either, although they can help the review process.
 
-    ```
-    function _testPrivate() private {
-      ...
-    }
-    ```
+# Solidity Conventions
+
+In addition to the official Solidity Style Guide we have a number of other conventions that must be followed.
+
+* All state variables should be private.
+
+  Changes to state should be accompanied by events, and in some cases it is not correct to arbitrarily set state. Encapsulating variables as private and only allowing modification via setters enables us to ensure that events and other rules are followed reliably and prevents this kind of user error.
+
+* Internal or private state variables or functions should have an underscore prefix.
+
+  ```solidity
+  contract TestContract {
+      uint256 private _privateVar;
+      uint256 internal _internalVar;
+      function _testInternal() internal { ... }
+      function _testPrivate() private { ... }
+  }
+  ```
 
 * Events should be emitted immediately after the state change that they
-  represent, and consequently they should be named in past tense.
+  represent, and should be named in the past tense.
 
-    ```
-    function _burn(address who, uint256 value) internal {
+  ```solidity
+  function _burn(address who, uint256 value) internal {
       super._burn(who, value);
       emit TokensBurned(who, value);
-    }
-    ```
+  }
+  ```
 
   Some standards (e.g. ERC20) use present tense, and in those cases the
-  standard specification prevails.
+  standard specification is used.
   
 * Interface names should have a capital I prefix.
 
-    ```
-    interface IERC777 {
-    ```
-
-
-## Tests
-
-* Tests Must be Written Elegantly
-
-    Tests are a good way to show how to use the library, and maintaining them is extremely necessary. Don't write long tests, write helper functions to make them be as short and concise as possible (they should take just a few lines each), and use good variable names.
-
-* Tests Must not be Random
+  ```solidity
+  interface IERC777 {
+  ```
 
-    Inputs for tests should not be generated randomly. Accounts used to create test contracts are an exception, those can be random. Also, the type and structure of outputs should be checked.
+* Unchecked arithmetic blocks should contain comments explaining why overflow is guaranteed not to happen. If the reason is immediately apparent from the line above the unchecked block, the comment may be omitted.

LICENSE

@@ -1,6 +1,6 @@
 The MIT License (MIT)
 
-Copyright (c) 2016-2022 zOS Global Limited and contributors
+Copyright (c) 2016-2023 zOS Global Limited and contributors
 
 Permission is hereby granted, free of charge, to any person obtaining
 a copy of this software and associated documentation files (the

README.md

@@ -1,9 +1,10 @@
 # <img src="logo.svg" alt="OpenZeppelin" height="40px">
 
-[![Docs](https://img.shields.io/badge/docs-%F0%9F%93%84-blue)](https://docs.openzeppelin.com/contracts)
 [![NPM Package](https://img.shields.io/npm/v/@openzeppelin/contracts.svg)](https://www.npmjs.org/package/@openzeppelin/contracts)
 [![Coverage Status](https://codecov.io/gh/OpenZeppelin/openzeppelin-contracts/graph/badge.svg)](https://codecov.io/gh/OpenZeppelin/openzeppelin-contracts)
-[![gitpoap badge](https://public-api.gitpoap.io/v1/repo/OpenZeppelin/openzeppelin-contracts/badge)](https://www.gitpoap.io/gh/OpenZeppelin/openzeppelin-contracts)
+[![GitPOAPs](https://public-api.gitpoap.io/v1/repo/OpenZeppelin/openzeppelin-contracts/badge)](https://www.gitpoap.io/gh/OpenZeppelin/openzeppelin-contracts)
+[![Docs](https://img.shields.io/badge/docs-%F0%9F%93%84-yellow)](https://docs.openzeppelin.com/contracts)
+[![Forum](https://img.shields.io/badge/forum-%F0%9F%92%AC-yellow)](https://docs.openzeppelin.com/contracts)
 
 **A library for secure smart contract development.** Build on a solid foundation of community-vetted code.
 
@@ -19,7 +20,7 @@
 
 ### Installation
 
-```console
+```
 $ npm install @openzeppelin/contracts
 ```
 
@@ -52,7 +53,6 @@ The guides in the [documentation site](https://docs.openzeppelin.com/contracts)
 
 * [Access Control](https://docs.openzeppelin.com/contracts/access-control): decide who can perform each of the actions on your system.
 * [Tokens](https://docs.openzeppelin.com/contracts/tokens): create tradeable assets or collectives, and distribute them via [Crowdsales](https://docs.openzeppelin.com/contracts/crowdsales).
-* [Gas Station Network](https://docs.openzeppelin.com/contracts/gsn): let your users interact with your contracts without having to pay for gas themselves.
 * [Utilities](https://docs.openzeppelin.com/contracts/utilities): generic useful tools including non-overflowing math, signature verification, and trustless paying systems.
 
 The [full API](https://docs.openzeppelin.com/contracts/api/token/ERC20) is also thoroughly documented, and serves as a great reference when developing your smart contract application. You can also ask for help or follow Contracts's development in the [community forum](https://forum.openzeppelin.com).
@@ -65,15 +65,17 @@ Finally, you may want to take a look at the [guides on our blog](https://blog.op
 
 ## Security
 
-This project is maintained by [OpenZeppelin](https://openzeppelin.com), and developed following our high standards for code quality and security. OpenZeppelin Contracts is meant to provide tested and community-audited code, but please use common sense when doing anything that deals with real money! We take no responsibility for your implementation decisions and any security problems you might experience.
+This project is maintained by [OpenZeppelin](https://openzeppelin.com) with the goal of providing a secure and reliable library of smart contract components for the ecosystem. We address security through risk management in various areas such as engineering and open source best practices, scoping and API design, multi-layered review processes, and incident response preparedness.
+
+The security policy is detailed in [`SECURITY.md`](./SECURITY.md), and specifies how you can report security vulnerabilities, which versions will receive security patches, and how to stay informed about them. We run a [bug bounty program on Immunefi](https://immunefi.com/bounty/openzeppelin) to reward the responsible disclosure of vulnerabilities.
 
-The core development principles and strategies that OpenZeppelin Contracts is based on include: security in depth, simple and modular code, clarity-driven naming conventions, comprehensive unit testing, pre-and-post-condition sanity checks, code consistency, and regular audits.
+The engineering guidelines we follow to promote project quality can be found in [`GUIDELINES.md`](./GUIDELINES.md).
 
-The latest audit was done on October 2018 on version 2.0.0.
+Past audits can be found in [`audits/`](./audits).
 
-We have a [**bug bounty program** on Immunefi](https://www.immunefi.com/bounty/openzeppelin). Please report any security issues you find through the Immunefi dashboard, or reach out to security@openzeppelin.com.
+Smart contracts are a nascent techology and carry a high level of technical risk and uncertainty. Although OpenZeppelin is well known for its security audits, using OpenZeppelin Contracts is not a substitute for a security audit.
 
-Critical bug fixes will be backported to past major releases.
+OpenZeppelin Contracts is made available under the MIT License, which disclaims all warranties in relation to the project and which limits the liability of those that contribute and maintain the project, including OpenZeppelin. As set out further in the Terms, you acknowledge that you are solely responsible for any use of OpenZeppelin Contracts and you assume all risks associated with any such use.
 
 ## Contribute
 
@@ -82,3 +84,7 @@ OpenZeppelin Contracts exists thanks to its contributors. There are many ways yo
 ## License
 
 OpenZeppelin Contracts is released under the [MIT License](LICENSE).
+
+## Legal
+
+Your use of this Project is governed by the terms found at www.openzeppelin.com/tos (the "Terms").

RELEASING.md

@@ -1,36 +1,47 @@
 # Releasing
 
-> Visit the documentation for [details about release schedule].
+> Visit the documentation for [details about release schedule](https://docs.openzeppelin.com/contracts/releases-stability).
 
-Start on an up-to-date `master` branch.
+OpenZeppelin Contracts uses a fully automated release process that takes care of compiling, packaging, and publishing the library, all of which is carried out in a clean CI environment (GitHub Actions), implemented in the ([`release-cycle`](.github/workflows/release-cycle.yml)) workflow. This helps to reduce the potential for human error and inconsistencies, and ensures that the release process is ongoing and reliable.
 
-Create the release branch with `npm run release start minor`.
+## Changesets
 
-Publish a release candidate with `npm run release rc`.
+[Changesets](https://github.com/changesets/changesets/) is used as part of our release process for `CHANGELOG.md` management. Each change that is relevant for the codebase is expected to include a changeset.
 
-Publish the final release with `npm run release final`.
+## Branching model
 
-Follow the general [OpenZeppelin Contracts release checklist].
+The release cycle happens on release branches called `release-vX.Y`. Each of these branches starts as a release candidate (rc) and is eventually promoted to final.
 
-[details about release schedule]: https://docs.openzeppelin.com/contracts/releases-stability
-[OpenZeppelin Contracts release checklist]: https://github.com/OpenZeppelin/code-style/blob/master/RELEASE_CHECKLIST.md
+A release branch can be updated with cherry-picked patches from `master`, or may sometimes be committed to directly in the case of old releases. These commits will lead to a new release candidate or a patch increment depending on the state of the release branch.
 
+```mermaid
+  %%{init: {'gitGraph': {'mainBranchName': 'master'}} }%%
+  gitGraph
+    commit id: "Feature A"
+    commit id: "Feature B"
+    branch release-vX.Y
+    commit id: "Start release"
+    commit id: "Release vX.Y.0-rc.0"
 
-## Merging the release branch
+    checkout master
+    commit id: "Feature C"
+    commit id: "Fix A"
 
-After the final release, the release branch should be merged back into `master`. This merge must not be squashed because it would lose the tagged release commit. Since the GitHub repo is set up to only allow squashed merges, the merge should be done locally and pushed.
+    checkout release-vX.Y
+    cherry-pick id: "Fix A" tag: ""
+    commit id: "Release vX.Y.0-rc.1"
+    commit id: "Release vX.Y.0"
 
-Make sure to have the latest changes from `upstream` in your local release branch.
+    checkout master
+    merge release-vX.Y
+    commit id: "Feature D"
+    commit id: "Patch B"
 
+    checkout release-vX.Y
+    cherry-pick id: "Patch B" tag: ""
+    commit id: "Release vX.Y.1"
+    
+    checkout master
+    merge release-vX.Y
+    commit id: "Feature E"
 ```
-git checkout release-vX.Y.Z
-git pull upstream
-```
-
-```
-git checkout master
-git merge --no-ff release-vX.Y.Z
-git push upstream master
-```
-
-The release branch can then be deleted on GitHub.

SECURITY.md

@@ -1,20 +1,42 @@
 # Security Policy
 
+Security vulnerabilities should be disclosed to the project maintainers through [Immunefi], or alternatively by email to security@openzeppelin.com.
+
+[Immunefi]: https://immunefi.com/bounty/openzeppelin
+
 ## Bug Bounty
 
-We have a [**bug bounty program** on Immunefi](https://www.immunefi.com/bounty/openzeppelin). Please report any security issues you find through the Immunefi dashboard, or reach out to security@openzeppelin.com.
+Responsible disclosure of security vulnerabilities is rewarded through a bug bounty program on [Immunefi].
+
+There is a bonus reward for issues introduced in release candidates that are reported before making it into a stable release.
+
+## Security Patches
+
+Security vulnerabilities will be patched as soon as responsibly possible, and published as an advisory on this repository (see [advisories]) and on the affected npm packages.
+
+[advisories]: https://github.com/OpenZeppelin/openzeppelin-contracts/security/advisories
+
+Projects that build on OpenZeppelin Contracts are encouraged to clearly state, in their source code and websites, how to be contacted about security issues in the event that a direct notification is considered necessary. We recommend including it in the NatSpec for the contract as `/// @custom:security-contact security@example.com`.
+
+Additionally, we recommend installing the library through npm and setting up vulnerability alerts such as [Dependabot].
+
+[Dependabot]: https://docs.github.com/en/code-security/supply-chain-security/understanding-your-software-supply-chain/about-supply-chain-security#what-is-dependabot
+
+### Supported Versions
+
+Security patches will be released for the latest minor of a given major release. For example, if an issue is found in versions >=4.6.0 and the latest is 4.8.0, the patch will be released only in version 4.8.1.
 
-Critical bug fixes will be backported to past major releases.
+Only critical severity bug fixes will be backported to past major releases.
 
-## Supported Versions
+| Version | Critical security fixes | Other security fixes |
+| ------- | ----------------------- | -------------------- |
+| 4.x     | :white_check_mark:      | :white_check_mark:   |
+| 3.4     | :white_check_mark:      | :x:                  |
+| 2.5     | :white_check_mark:      | :x:                  |
+| < 2.0   | :x:                     | :x:                  |
 
-The recommendation is to use the latest version available.
+Note as well that the Solidity language itself only guarantees security updates for the latest release.
 
-| Version | Supported                            |
-| ------- | ------------------------------------ |
-| 4.x     | :white_check_mark::white_check_mark: |
-| 3.4     | :white_check_mark:                   |
-| 2.5     | :white_check_mark:                   |
-| < 2.0   | :x:                                  |
+## Legal
 
-Note that the Solidity language itself only guarantees security updates for the latest release.
+Smart contracts are a nascent techology and carry a high level of technical risk and uncertainty.  OpenZeppelin Contracts is made available under the MIT License, which disclaims all warranties in relation to the project and which limits the liability of those that contribute and maintain the project, including OpenZeppelin. Your use of the project is also governed by the terms found at www.openzeppelin.com/tos (the "Terms"). As set out in the Terms, you are solely responsible for any use of OpenZeppelin Contracts and you assume all risks associated with any such use. This Security Policy in no way evidences or represents an on-going duty by any contributor, including OpenZeppelin, to correct any flaws or alert you to all or any of the potential risks of utilizing the project.

audits/2017-03.md

@@ -1,6 +1,6 @@
 # OpenZeppelin Audit
 
-NOTE ON 2021-07-19: This report makes reference to Zeppelin, OpenZeppelin, OpenZeppelin [C]ontracts, the OpenZeppelin team, and OpenZeppelin library. Many of these things have since been renamed and know that this audit applies to what is currently called the OpenZeppelin Contracts which are maintained by the OpenZeppelin Conracts Community.
+NOTE ON 2021-07-19: This report makes reference to Zeppelin, OpenZeppelin, OpenZeppelin Contracts, the OpenZeppelin team, and OpenZeppelin library. Many of these things have since been renamed and know that this audit applies to what is currently called the OpenZeppelin Contracts which are maintained by the OpenZeppelin Contracts Community.
 
 March, 2017
 Authored by Dennis Peterson and Peter Vessenes

audits/README.md

@@ -0,0 +1,15 @@
+# Audits
+
+| Date         | Version | Commit    | Auditor      | Scope                | Links                                                       |
+| ------------ | ------- | --------- | ------------ | -------------------- | ----------------------------------------------------------- |
+| October 2022 | v4.8.0  | `14f98db` | OpenZeppelin | ERC4626, Checkpoints | [🔗](./2022-10-ERC4626.pdf) [🔗](./2022-10-Checkpoints.pdf) |
+| October 2018 | v2.0.0  | `dac5bcc` | LevelK       | Everything           | [🔗](./2018-10.pdf)                                         |
+| March 2017   | v1.0.4  | `9c5975a` | New Alchemy  | Everything           | [🔗](./2017-03.md)                                          |
+
+# Formal Verification
+
+| Date         | Version | Commit    | Tool    | Scope                                                                                                                            | Links                                |
+| ------------ | ------- | --------- | ------- | -------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------ |
+| May 2022     | v4.7.0  | `109778c` | Certora | Initializable, GovernorPreventLateQuorum, ERC1155Burnable, ERC1155Pausable, ERC1155Supply, ERC1155Holder, ERC1155Receiver        | [🔗](../certora/reports/2022-05.pdf) |
+| March 2022   | v4.4.0  | `4088540` | Certora | ERC20Votes, ERC20FlashMint, ERC20Wrapper, TimelockController, ERC721Votes, Votes, AccessControl, ERC1155                         | [🔗](../certora/reports/2022-03.pdf) |
+| October 2021 | v4.4.0  | `4088540` | Certora | Governor, GovernorCountingSimple, GovernorProposalThreshold, GovernorTimelockControl, GovernorVotes, GovernorVotesQuorumFraction | [🔗](../certora/reports/2021-10.pdf) |

certora/scripts/noCI/Round1/verifyAll.sh

@@ -1,38 +0,0 @@
-#!/usr/bin/env bash
-
-set -euxo pipefail
-
-for contract in certora/harnesses/Wizard*.sol;
-do
-    # NOTE: some spec files are not governor related, and should be run on Wizard*.sol
-    for spec in certora/specs/*.spec;
-    do
-        contractFile=$(basename $contract)
-        specFile=$(basename $spec)
-        if [[ "${specFile%.*}" != "RulesInProgress" ]];
-        then
-            echo "Processing ${contractFile%.*} with $specFile"
-            if [[ "${contractFile%.*}" = *"WizardControl"* ]];
-            then
-                certoraRun \
-                    certora/harnesses/ERC20VotesHarness.sol certora/harnesses/$contractFile \
-                    --link ${contractFile%.*}:token=ERC20VotesHarness \
-                    --verify ${contractFile%.*}:certora/specs/$specFile "$@" \
-                    --solc solc \
-                    --optimistic_loop \
-                    --disableLocalTypeChecking \
-                    --settings -copyLoopUnroll=4 \
-                    --msg "checking $specFile on ${contractFile%.*}"
-            else
-                certoraRun \
-                    certora/harnesses/ERC20VotesHarness.sol certora/harnesses/$contractFile \
-                    --verify ${contractFile%.*}:certora/specs/$specFile "$@" \
-                    --solc solc \
-                    --optimistic_loop \
-                    --disableLocalTypeChecking \
-                    --settings -copyLoopUnroll=4 \
-                    --msg "checking $specFile on ${contractFile%.*}"
-            fi
-        fi
-    done
-done

certora/scripts/noCI/sanity/sanityGovernor.sh

@@ -5,7 +5,7 @@ set -euxo pipefail
 for f in certora/harnesses/Wizard*.sol
 do
     echo "Processing $f"
-    file=$(basename $f)
+    file="$(basename $f)"
     echo ${file%.*}
     certoraRun certora/harnesses/$file \
         --verify ${file%.*}:certora/specs/sanity.spec "$@" \

contracts/access/AccessControl.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-// OpenZeppelin Contracts (last updated v4.7.0) (access/AccessControl.sol)
+// OpenZeppelin Contracts (last updated v4.8.0) (access/AccessControl.sol)
 
 pragma solidity ^0.8.0;
 
@@ -19,14 +19,14 @@ import "../utils/introspection/ERC165.sol";
  * in the external API and be unique. The best way to achieve this is by
  * using `public constant` hash digests:
  *
- * ```
+ * ```solidity
  * bytes32 public constant MY_ROLE = keccak256("MY_ROLE");
  * ```
  *
  * Roles can be used to represent a set of permissions. To restrict access to a
  * function call, use {hasRole}:
  *
- * ```
+ * ```solidity
  * function foo() public {
  *     require(hasRole(MY_ROLE, msg.sender));
  *     ...
@@ -44,7 +44,8 @@ import "../utils/introspection/ERC165.sol";
  *
  * WARNING: The `DEFAULT_ADMIN_ROLE` is also its own admin: it has permission to
  * grant and revoke this role. Extra precautions should be taken to secure
- * accounts that have been granted it.
+ * accounts that have been granted it. We recommend using {AccessControlDefaultAdminRules}
+ * to enforce additional security measures for this role.
  */
 abstract contract AccessControl is Context, IAccessControl, ERC165 {
     struct RoleData {

contracts/access/AccessControlDefaultAdminRules.sol

@@ -0,0 +1,240 @@
+// SPDX-License-Identifier: MIT
+// OpenZeppelin Contracts (last updated v4.8.0) (access/AccessControlDefaultAdminRules.sol)
+
+pragma solidity ^0.8.0;
+
+import "./AccessControl.sol";
+import "./IAccessControlDefaultAdminRules.sol";
+import "../utils/math/SafeCast.sol";
+import "../interfaces/IERC5313.sol";
+
+/**
+ * @dev Extension of {AccessControl} that allows specifying special rules to manage
+ * the `DEFAULT_ADMIN_ROLE` holder, which is a sensitive role with special permissions
+ * over other roles that may potentially have privileged rights in the system.
+ *
+ * If a specific role doesn't have an admin role assigned, the holder of the
+ * `DEFAULT_ADMIN_ROLE` will have the ability to grant it and revoke it.
+ *
+ * This contract implements the following risk mitigations on top of {AccessControl}:
+ *
+ * * Only one account holds the `DEFAULT_ADMIN_ROLE` since deployment until it's potentially renounced.
+ * * Enforce a 2-step process to transfer the `DEFAULT_ADMIN_ROLE` to another account.
+ * * Enforce a configurable delay between the two steps, with the ability to cancel in between.
+ *   - Even after the timer has passed to avoid locking it forever.
+ * * It is not possible to use another role to manage the `DEFAULT_ADMIN_ROLE`.
+ *
+ * Example usage:
+ *
+ * ```solidity
+ * contract MyToken is AccessControlDefaultAdminRules {
+ *   constructor() AccessControlDefaultAdminRules(
+ *     3 days,
+ *     msg.sender // Explicit initial `DEFAULT_ADMIN_ROLE` holder
+ *    ) {}
+ *}
+ * ```
+ *
+ * NOTE: The `delay` can only be set in the constructor and is fixed thereafter.
+ *
+ * _Available since v4.9._
+ */
+abstract contract AccessControlDefaultAdminRules is IAccessControlDefaultAdminRules, IERC5313, AccessControl {
+    uint48 private immutable _defaultAdminDelay;
+
+    address private _currentDefaultAdmin;
+    address private _pendingDefaultAdmin;
+
+    uint48 private _defaultAdminTransferDelayedUntil;
+
+    /**
+     * @dev Sets the initial values for {defaultAdminDelay} in seconds and {defaultAdmin}.
+     *
+     * The `defaultAdminDelay` value is immutable. It can only be set at the constructor.
+     */
+    constructor(uint48 defaultAdminDelay_, address initialDefaultAdmin) {
+        _defaultAdminDelay = defaultAdminDelay_;
+        _grantRole(DEFAULT_ADMIN_ROLE, initialDefaultAdmin);
+    }
+
+    /**
+     * @dev See {IERC5313-owner}.
+     */
+    function owner() public view virtual returns (address) {
+        return defaultAdmin();
+    }
+
+    /**
+     * @inheritdoc IAccessControlDefaultAdminRules
+     */
+    function defaultAdminDelay() public view virtual returns (uint48) {
+        return _defaultAdminDelay;
+    }
+
+    /**
+     * @inheritdoc IAccessControlDefaultAdminRules
+     */
+    function defaultAdmin() public view virtual returns (address) {
+        return _currentDefaultAdmin;
+    }
+
+    /**
+     * @inheritdoc IAccessControlDefaultAdminRules
+     */
+    function pendingDefaultAdmin() public view virtual returns (address) {
+        return _pendingDefaultAdmin;
+    }
+
+    /**
+     * @inheritdoc IAccessControlDefaultAdminRules
+     */
+    function defaultAdminTransferDelayedUntil() public view virtual returns (uint48) {
+        return _defaultAdminTransferDelayedUntil;
+    }
+
+    /**
+     * @dev See {IERC165-supportsInterface}.
+     */
+    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
+        return interfaceId == type(IAccessControlDefaultAdminRules).interfaceId || super.supportsInterface(interfaceId);
+    }
+
+    /**
+     * @inheritdoc IAccessControlDefaultAdminRules
+     */
+    function beginDefaultAdminTransfer(address newAdmin) public virtual onlyRole(DEFAULT_ADMIN_ROLE) {
+        _beginDefaultAdminTransfer(newAdmin);
+    }
+
+    /**
+     * @inheritdoc IAccessControlDefaultAdminRules
+     */
+    function acceptDefaultAdminTransfer() public virtual {
+        require(_msgSender() == pendingDefaultAdmin(), "AccessControl: pending admin must accept");
+        _acceptDefaultAdminTransfer();
+    }
+
+    /**
+     * @inheritdoc IAccessControlDefaultAdminRules
+     */
+    function cancelDefaultAdminTransfer() public virtual onlyRole(DEFAULT_ADMIN_ROLE) {
+        _resetDefaultAdminTransfer();
+    }
+
+    /**
+     * @dev Revokes `role` from the calling account.
+     *
+     * For `DEFAULT_ADMIN_ROLE`, only allows renouncing in two steps, so it's required
+     * that the {defaultAdminTransferDelayedUntil} has passed and the pending default admin is the zero address.
+     * After its execution, it will not be possible to call `onlyRole(DEFAULT_ADMIN_ROLE)`
+     * functions.
+     *
+     * For other roles, see {AccessControl-renounceRole}.
+     *
+     * NOTE: Renouncing `DEFAULT_ADMIN_ROLE` will leave the contract without a defaultAdmin,
+     * thereby disabling any functionality that is only available to the default admin, and the
+     * possibility of reassigning a non-administrated role.
+     */
+    function renounceRole(bytes32 role, address account) public virtual override(AccessControl, IAccessControl) {
+        if (role == DEFAULT_ADMIN_ROLE) {
+            require(
+                pendingDefaultAdmin() == address(0) && _hasDefaultAdminTransferDelayPassed(),
+                "AccessControl: only can renounce in two delayed steps"
+            );
+        }
+        super.renounceRole(role, account);
+    }
+
+    /**
+     * @dev See {AccessControl-grantRole}. Reverts for `DEFAULT_ADMIN_ROLE`.
+     */
+    function grantRole(bytes32 role, address account) public virtual override(AccessControl, IAccessControl) {
+        require(role != DEFAULT_ADMIN_ROLE, "AccessControl: can't directly grant default admin role");
+        super.grantRole(role, account);
+    }
+
+    /**
+     * @dev See {AccessControl-revokeRole}. Reverts for `DEFAULT_ADMIN_ROLE`.
+     */
+    function revokeRole(bytes32 role, address account) public virtual override(AccessControl, IAccessControl) {
+        require(role != DEFAULT_ADMIN_ROLE, "AccessControl: can't directly revoke default admin role");
+        super.revokeRole(role, account);
+    }
+
+    /**
+     * @dev See {AccessControl-_setRoleAdmin}. Reverts for `DEFAULT_ADMIN_ROLE`.
+     */
+    function _setRoleAdmin(bytes32 role, bytes32 adminRole) internal virtual override {
+        require(role != DEFAULT_ADMIN_ROLE, "AccessControl: can't violate default admin rules");
+        super._setRoleAdmin(role, adminRole);
+    }
+
+    /**
+     * @dev Grants `role` to `account`.
+     *
+     * For `DEFAULT_ADMIN_ROLE`, it only allows granting if there isn't already a role's holder
+     * or if the role has been previously renounced.
+     *
+     * For other roles, see {AccessControl-renounceRole}.
+     *
+     * NOTE: Exposing this function through another mechanism may make the
+     * `DEFAULT_ADMIN_ROLE` assignable again. Make sure to guarantee this is
+     * the expected behavior in your implementation.
+     */
+    function _grantRole(bytes32 role, address account) internal virtual override {
+        if (role == DEFAULT_ADMIN_ROLE) {
+            require(defaultAdmin() == address(0), "AccessControl: default admin already granted");
+            _currentDefaultAdmin = account;
+        }
+        super._grantRole(role, account);
+    }
+
+    /**
+     * @dev See {acceptDefaultAdminTransfer}.
+     *
+     * Internal function without access restriction.
+     */
+    function _acceptDefaultAdminTransfer() internal virtual {
+        require(_hasDefaultAdminTransferDelayPassed(), "AccessControl: transfer delay not passed");
+        _revokeRole(DEFAULT_ADMIN_ROLE, defaultAdmin());
+        _grantRole(DEFAULT_ADMIN_ROLE, pendingDefaultAdmin());
+        _resetDefaultAdminTransfer();
+    }
+
+    /**
+     * @dev See {beginDefaultAdminTransfer}.
+     *
+     * Internal function without access restriction.
+     */
+    function _beginDefaultAdminTransfer(address newAdmin) internal virtual {
+        _defaultAdminTransferDelayedUntil = SafeCast.toUint48(block.timestamp) + defaultAdminDelay();
+        _pendingDefaultAdmin = newAdmin;
+        emit DefaultAdminRoleChangeStarted(pendingDefaultAdmin(), defaultAdminTransferDelayedUntil());
+    }
+
+    /**
+     * @dev See {AccessControl-_revokeRole}.
+     */
+    function _revokeRole(bytes32 role, address account) internal virtual override {
+        if (role == DEFAULT_ADMIN_ROLE) {
+            delete _currentDefaultAdmin;
+        }
+        super._revokeRole(role, account);
+    }
+
+    /**
+     * @dev Resets the pending default admin and delayed until.
+     */
+    function _resetDefaultAdminTransfer() private {
+        delete _pendingDefaultAdmin;
+        delete _defaultAdminTransferDelayedUntil;
+    }
+
+    /**
+     * @dev Checks if a {defaultAdminTransferDelayedUntil} has been set and passed.
+     */
+    function _hasDefaultAdminTransferDelayPassed() private view returns (bool) {
+        uint48 delayedUntil = defaultAdminTransferDelayedUntil();
+        return delayedUntil > 0 && delayedUntil < block.timestamp;
+    }
+}

contracts/access/IAccessControlDefaultAdminRules.sol

@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: MIT
+// OpenZeppelin Contracts v4.9.0 (access/IAccessControlDefaultAdminRules.sol)
+
+pragma solidity ^0.8.0;
+
+import "./IAccessControl.sol";
+
+/**
+ * @dev External interface of AccessControlDefaultAdminRules declared to support ERC165 detection.
+ *
+ * _Available since v4.9._
+ */
+interface IAccessControlDefaultAdminRules is IAccessControl {
+    /**
+     * @dev Emitted when a `DEFAULT_ADMIN_ROLE` transfer is started, setting `newDefaultAdmin`
+     * as the next default admin, which will have rights to claim the `DEFAULT_ADMIN_ROLE`
+     * after `defaultAdminTransferDelayedUntil` has passed.
+     */
+    event DefaultAdminRoleChangeStarted(address indexed newDefaultAdmin, uint48 defaultAdminTransferDelayedUntil);
+
+    /**
+     * @dev Returns the delay between each `DEFAULT_ADMIN_ROLE` transfer.
+     */
+    function defaultAdminDelay() external view returns (uint48);
+
+    /**
+     * @dev Returns the address of the current `DEFAULT_ADMIN_ROLE` holder.
+     */
+    function defaultAdmin() external view returns (address);
+
+    /**
+     * @dev Returns the address of the pending `DEFAULT_ADMIN_ROLE` holder.
+     */
+    function pendingDefaultAdmin() external view returns (address);
+
+    /**
+     * @dev Returns the timestamp after which the pending default admin can claim the `DEFAULT_ADMIN_ROLE`.
+     */
+    function defaultAdminTransferDelayedUntil() external view returns (uint48);
+
+    /**
+     * @dev Starts a `DEFAULT_ADMIN_ROLE` transfer by setting a pending default admin
+     * and a timer to pass.
+     *
+     * Requirements:
+     *
+     * - Only can be called by the current `DEFAULT_ADMIN_ROLE` holder.
+     *
+     * Emits a {DefaultAdminRoleChangeStarted}.
+     */
+    function beginDefaultAdminTransfer(address newAdmin) external;
+
+    /**
+     * @dev Completes a `DEFAULT_ADMIN_ROLE` transfer.
+     *
+     * Requirements:
+     *
+     * - Caller should be the pending default admin.
+     * - `DEFAULT_ADMIN_ROLE` should be granted to the caller.
+     * - `DEFAULT_ADMIN_ROLE` should be revoked from the previous holder.
+     */
+    function acceptDefaultAdminTransfer() external;
+
+    /**
+     * @dev Cancels a `DEFAULT_ADMIN_ROLE` transfer.
+     *
+     * Requirements:
+     *
+     * - Can be called even after the timer has passed.
+     * - Can only be called by the current `DEFAULT_ADMIN_ROLE` holder.
+     */
+    function cancelDefaultAdminTransfer() external;
+}

contracts/access/Ownable.sol

@@ -53,10 +53,10 @@ abstract contract Ownable is Context {
 
     /**
      * @dev Leaves the contract without owner. It will not be possible to call
-     * `onlyOwner` functions anymore. Can only be called by the current owner.
+     * `onlyOwner` functions. Can only be called by the current owner.
      *
      * NOTE: Renouncing ownership will leave the contract without an owner,
-     * thereby removing any functionality that is only available to the owner.
+     * thereby disabling any functionality that is only available to the owner.
      */
     function renounceOwnership() public virtual onlyOwner {
         _transferOwnership(address(0));

contracts/access/Ownable2Step.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-// OpenZeppelin Contracts (last updated v4.7.0) (access/Ownable.sol)
+// OpenZeppelin Contracts (last updated v4.8.0) (access/Ownable2Step.sol)
 
 pragma solidity ^0.8.0;
 
@@ -49,7 +49,7 @@ abstract contract Ownable2Step is Ownable {
     /**
      * @dev The new owner accepts the ownership transfer.
      */
-    function acceptOwnership() external {
+    function acceptOwnership() public virtual {
         address sender = _msgSender();
         require(pendingOwner() == sender, "Ownable2Step: caller is not the new owner");
         _transferOwnership(sender);

contracts/access/README.adoc

@@ -12,6 +12,8 @@ This directory provides ways to restrict who can access the functions of a contr
 
 {{Ownable}}
 
+{{Ownable2Step}}
+
 {{IAccessControl}}
 
 {{AccessControl}}
@@ -21,3 +23,5 @@ This directory provides ways to restrict who can access the functions of a contr
 {{IAccessControlEnumerable}}
 
 {{AccessControlEnumerable}}
+
+{{AccessControlDefaultAdminRules}}

contracts/crosschain/arbitrum/CrossChainEnabledArbitrumL2.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-// OpenZeppelin Contracts (last updated v4.7.0) (crosschain/arbitrum/CrossChainEnabledArbitrumL2.sol)
+// OpenZeppelin Contracts (last updated v4.8.0) (crosschain/arbitrum/CrossChainEnabledArbitrumL2.sol)
 
 pragma solidity ^0.8.4;
 

contracts/crosschain/arbitrum/LibArbitrumL1.sol

@@ -1,10 +1,9 @@
 // SPDX-License-Identifier: MIT
-// OpenZeppelin Contracts (last updated v4.7.0) (crosschain/arbitrum/LibArbitrumL1.sol)
+// OpenZeppelin Contracts (last updated v4.8.0) (crosschain/arbitrum/LibArbitrumL1.sol)
 
 pragma solidity ^0.8.4;
 
 import {IBridge as ArbitrumL1_Bridge} from "../../vendor/arbitrum/IBridge.sol";
-import {IInbox as ArbitrumL1_Inbox} from "../../vendor/arbitrum/IInbox.sol";
 import {IOutbox as ArbitrumL1_Outbox} from "../../vendor/arbitrum/IOutbox.sol";
 import "../errors.sol";
 

contracts/crosschain/arbitrum/LibArbitrumL2.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-// OpenZeppelin Contracts (last updated v4.7.0) (crosschain/arbitrum/LibArbitrumL2.sol)
+// OpenZeppelin Contracts (last updated v4.8.0) (crosschain/arbitrum/LibArbitrumL2.sol)
 
 pragma solidity ^0.8.4;
 

contracts/crosschain/polygon/CrossChainEnabledPolygonChild.sol

@@ -59,7 +59,7 @@ abstract contract CrossChainEnabledPolygonChild is IFxMessageProcessor, CrossCha
      * then security could be compromised.
      */
     function processMessageFromRoot(
-        uint256, /* stateId */
+        uint256 /* stateId */,
         address rootMessageSender,
         bytes calldata data
     ) external override nonReentrant {

contracts/finance/PaymentSplitter.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-// OpenZeppelin Contracts (last updated v4.7.0) (finance/PaymentSplitter.sol)
+// OpenZeppelin Contracts (last updated v4.8.0) (finance/PaymentSplitter.sol)
 
 pragma solidity ^0.8.0;
 

contracts/finance/VestingWallet.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-// OpenZeppelin Contracts (last updated v4.7.0) (finance/VestingWallet.sol)
+// OpenZeppelin Contracts (last updated v4.8.0) (finance/VestingWallet.sol)
 pragma solidity ^0.8.0;
 
 import "../token/ERC20/utils/SafeERC20.sol";
@@ -29,11 +29,7 @@ contract VestingWallet is Context {
     /**
      * @dev Set the beneficiary, start timestamp and vesting duration of the vesting wallet.
      */
-    constructor(
-        address beneficiaryAddress,
-        uint64 startTimestamp,
-        uint64 durationSeconds
-    ) payable {
+    constructor(address beneficiaryAddress, uint64 startTimestamp, uint64 durationSeconds) payable {
         require(beneficiaryAddress != address(0), "VestingWallet: beneficiary is zero address");
         _beneficiary = beneficiaryAddress;
         _start = startTimestamp;

contracts/governance/Governor.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-// OpenZeppelin Contracts (last updated v4.7.0) (governance/Governor.sol)
+// OpenZeppelin Contracts (last updated v4.8.0) (governance/Governor.sol)
 
 pragma solidity ^0.8.0;
 
@@ -12,7 +12,6 @@ import "../utils/math/SafeCast.sol";
 import "../utils/structs/DoubleEndedQueue.sol";
 import "../utils/Address.sol";
 import "../utils/Context.sol";
-import "../utils/Timers.sol";
 import "./IGovernor.sol";
 
 /**
@@ -22,28 +21,36 @@ import "./IGovernor.sol";
  *
  * - A counting module must implement {quorum}, {_quorumReached}, {_voteSucceeded} and {_countVote}
  * - A voting module must implement {_getVotes}
- * - Additionanly, the {votingPeriod} must also be implemented
+ * - Additionally, the {votingPeriod} must also be implemented
  *
  * _Available since v4.3._
  */
 abstract contract Governor is Context, ERC165, EIP712, IGovernor, IERC721Receiver, IERC1155Receiver {
     using DoubleEndedQueue for DoubleEndedQueue.Bytes32Deque;
     using SafeCast for uint256;
-    using Timers for Timers.BlockNumber;
 
     bytes32 public constant BALLOT_TYPEHASH = keccak256("Ballot(uint256 proposalId,uint8 support)");
     bytes32 public constant EXTENDED_BALLOT_TYPEHASH =
         keccak256("ExtendedBallot(uint256 proposalId,uint8 support,string reason,bytes params)");
 
+    // solhint-disable var-name-mixedcase
     struct ProposalCore {
-        Timers.BlockNumber voteStart;
-        Timers.BlockNumber voteEnd;
+        // --- start retyped from Timers.BlockNumber at offset 0x00 ---
+        uint64 voteStart;
+        address proposer;
+        bytes4 __gap_unused0;
+        // --- start retyped from Timers.BlockNumber at offset 0x20 ---
+        uint64 voteEnd;
+        bytes24 __gap_unused1;
+        // --- Remaining fields starting at offset 0x40 ---------------
         bool executed;
         bool canceled;
     }
+    // solhint-enable var-name-mixedcase
 
     string private _name;
 
+    /// @custom:oz-retyped-from mapping(uint256 => Governor.ProposalCore)
     mapping(uint256 => ProposalCore) private _proposals;
 
     // This queue keeps track of the governor operating on itself. Calls to functions protected by the
@@ -95,10 +102,13 @@ abstract contract Governor is Context, ERC165, EIP712, IGovernor, IERC721Receive
         return
             interfaceId ==
             (type(IGovernor).interfaceId ^
+                type(IERC6372).interfaceId ^
+                this.cancel.selector ^
                 this.castVoteWithReasonAndParams.selector ^
                 this.castVoteWithReasonAndParamsBySig.selector ^
                 this.getVotesWithParams.selector) ||
-            interfaceId == type(IGovernor).interfaceId ||
+            // Previous interface for backwards compatibility
+            interfaceId == (type(IGovernor).interfaceId ^ type(IERC6372).interfaceId ^ this.cancel.selector) ||
             interfaceId == type(IERC1155Receiver).interfaceId ||
             super.supportsInterface(interfaceId);
     }
@@ -159,13 +169,15 @@ abstract contract Governor is Context, ERC165, EIP712, IGovernor, IERC721Receive
             revert("Governor: unknown proposal id");
         }
 
-        if (snapshot >= block.number) {
+        uint256 currentTimepoint = clock();
+
+        if (snapshot >= currentTimepoint) {
             return ProposalState.Pending;
         }
 
         uint256 deadline = proposalDeadline(proposalId);
 
-        if (deadline >= block.number) {
+        if (deadline >= currentTimepoint) {
             return ProposalState.Active;
         }
 
@@ -176,25 +188,32 @@ abstract contract Governor is Context, ERC165, EIP712, IGovernor, IERC721Receive
         }
     }
 
+    /**
+     * @dev Part of the Governor Bravo's interface: _"The number of votes required in order for a voter to become a proposer"_.
+     */
+    function proposalThreshold() public view virtual returns (uint256) {
+        return 0;
+    }
+
     /**
      * @dev See {IGovernor-proposalSnapshot}.
      */
     function proposalSnapshot(uint256 proposalId) public view virtual override returns (uint256) {
-        return _proposals[proposalId].voteStart.getDeadline();
+        return _proposals[proposalId].voteStart;
     }
 
     /**
      * @dev See {IGovernor-proposalDeadline}.
      */
     function proposalDeadline(uint256 proposalId) public view virtual override returns (uint256) {
-        return _proposals[proposalId].voteEnd.getDeadline();
+        return _proposals[proposalId].voteEnd;
     }
 
     /**
-     * @dev Part of the Governor Bravo's interface: _"The number of votes required in order for a voter to become a proposer"_.
+     * @dev Address of the proposer
      */
-    function proposalThreshold() public view virtual returns (uint256) {
-        return 0;
+    function _proposalProposer(uint256 proposalId) internal view virtual returns (address) {
+        return _proposals[proposalId].proposer;
     }
 
     /**
@@ -208,13 +227,9 @@ abstract contract Governor is Context, ERC165, EIP712, IGovernor, IERC721Receive
     function _voteSucceeded(uint256 proposalId) internal view virtual returns (bool);
 
     /**
-     * @dev Get the voting weight of `account` at a specific `blockNumber`, for a vote as described by `params`.
+     * @dev Get the voting weight of `account` at a specific `timepoint`, for a vote as described by `params`.
      */
-    function _getVotes(
-        address account,
-        uint256 blockNumber,
-        bytes memory params
-    ) internal view virtual returns (uint256);
+    function _getVotes(address account, uint256 timepoint, bytes memory params) internal view virtual returns (uint256);
 
     /**
      * @dev Register a vote for `proposalId` by `account` with a given `support`, voting `weight` and voting `params`.
@@ -248,8 +263,11 @@ abstract contract Governor is Context, ERC165, EIP712, IGovernor, IERC721Receive
         bytes[] memory calldatas,
         string memory description
     ) public virtual override returns (uint256) {
+        address proposer = _msgSender();
+        uint256 currentTimepoint = clock();
+
         require(
-            getVotes(_msgSender(), block.number - 1) >= proposalThreshold(),
+            getVotes(proposer, currentTimepoint - 1) >= proposalThreshold(),
             "Governor: proposer votes below proposal threshold"
         );
 
@@ -258,19 +276,24 @@ abstract contract Governor is Context, ERC165, EIP712, IGovernor, IERC721Receive
         require(targets.length == values.length, "Governor: invalid proposal length");
         require(targets.length == calldatas.length, "Governor: invalid proposal length");
         require(targets.length > 0, "Governor: empty proposal");
+        require(_proposals[proposalId].proposer == address(0), "Governor: proposal already exists");
 
-        ProposalCore storage proposal = _proposals[proposalId];
-        require(proposal.voteStart.isUnset(), "Governor: proposal already exists");
-
-        uint64 snapshot = block.number.toUint64() + votingDelay().toUint64();
-        uint64 deadline = snapshot + votingPeriod().toUint64();
+        uint256 snapshot = currentTimepoint + votingDelay();
+        uint256 deadline = snapshot + votingPeriod();
 
-        proposal.voteStart.setDeadline(snapshot);
-        proposal.voteEnd.setDeadline(deadline);
+        _proposals[proposalId] = ProposalCore({
+            proposer: proposer,
+            voteStart: snapshot.toUint64(),
+            voteEnd: deadline.toUint64(),
+            executed: false,
+            canceled: false,
+            __gap_unused0: 0,
+            __gap_unused1: 0
+        });
 
         emit ProposalCreated(
             proposalId,
-            _msgSender(),
+            proposer,
             targets,
             values,
             new string[](targets.length),
@@ -310,11 +333,26 @@ abstract contract Governor is Context, ERC165, EIP712, IGovernor, IERC721Receive
         return proposalId;
     }
 
+    /**
+     * @dev See {IGovernor-cancel}.
+     */
+    function cancel(
+        address[] memory targets,
+        uint256[] memory values,
+        bytes[] memory calldatas,
+        bytes32 descriptionHash
+    ) public virtual override returns (uint256) {
+        uint256 proposalId = hashProposal(targets, values, calldatas, descriptionHash);
+        require(state(proposalId) == ProposalState.Pending, "Governor: too late to cancel");
+        require(_msgSender() == _proposals[proposalId].proposer, "Governor: only proposer can cancel");
+        return _cancel(targets, values, calldatas, descriptionHash);
+    }
+
     /**
      * @dev Internal execution mechanism. Can be overridden to implement different execution mechanism
      */
     function _execute(
-        uint256, /* proposalId */
+        uint256 /* proposalId */,
         address[] memory targets,
         uint256[] memory values,
         bytes[] memory calldatas,
@@ -331,9 +369,9 @@ abstract contract Governor is Context, ERC165, EIP712, IGovernor, IERC721Receive
      * @dev Hook before execution is triggered.
      */
     function _beforeExecute(
-        uint256, /* proposalId */
+        uint256 /* proposalId */,
         address[] memory targets,
-        uint256[] memory, /* values */
+        uint256[] memory /* values */,
         bytes[] memory calldatas,
         bytes32 /*descriptionHash*/
     ) internal virtual {
@@ -350,10 +388,10 @@ abstract contract Governor is Context, ERC165, EIP712, IGovernor, IERC721Receive
      * @dev Hook after execution is triggered.
      */
     function _afterExecute(
-        uint256, /* proposalId */
-        address[] memory, /* targets */
-        uint256[] memory, /* values */
-        bytes[] memory, /* calldatas */
+        uint256 /* proposalId */,
+        address[] memory /* targets */,
+        uint256[] memory /* values */,
+        bytes[] memory /* calldatas */,
         bytes32 /*descriptionHash*/
     ) internal virtual {
         if (_executor() != address(this)) {
@@ -376,6 +414,7 @@ abstract contract Governor is Context, ERC165, EIP712, IGovernor, IERC721Receive
         bytes32 descriptionHash
     ) internal virtual returns (uint256) {
         uint256 proposalId = hashProposal(targets, values, calldatas, descriptionHash);
+
         ProposalState status = state(proposalId);
 
         require(
@@ -392,8 +431,8 @@ abstract contract Governor is Context, ERC165, EIP712, IGovernor, IERC721Receive
     /**
      * @dev See {IGovernor-getVotes}.
      */
-    function getVotes(address account, uint256 blockNumber) public view virtual override returns (uint256) {
-        return _getVotes(account, blockNumber, _defaultParams());
+    function getVotes(address account, uint256 timepoint) public view virtual override returns (uint256) {
+        return _getVotes(account, timepoint, _defaultParams());
     }
 
     /**
@@ -401,10 +440,10 @@ abstract contract Governor is Context, ERC165, EIP712, IGovernor, IERC721Receive
      */
     function getVotesWithParams(
         address account,
-        uint256 blockNumber,
+        uint256 timepoint,
         bytes memory params
     ) public view virtual override returns (uint256) {
-        return _getVotes(account, blockNumber, params);
+        return _getVotes(account, timepoint, params);
     }
 
     /**
@@ -522,7 +561,7 @@ abstract contract Governor is Context, ERC165, EIP712, IGovernor, IERC721Receive
         ProposalCore storage proposal = _proposals[proposalId];
         require(state(proposalId) == ProposalState.Active, "Governor: vote not currently active");
 
-        uint256 weight = _getVotes(account, proposal.voteStart.getDeadline(), params);
+        uint256 weight = _getVotes(account, proposal.voteStart, params);
         _countVote(proposalId, account, support, weight, params);
 
         if (params.length == 0) {
@@ -540,12 +579,9 @@ abstract contract Governor is Context, ERC165, EIP712, IGovernor, IERC721Receive
      * in a governance proposal to recover tokens or Ether that was sent to the governor contract by mistake.
      * Note that if the executor is simply the governor itself, use of `relay` is redundant.
      */
-    function relay(
-        address target,
-        uint256 value,
-        bytes calldata data
-    ) external virtual onlyGovernance {
-        Address.functionCallWithValue(target, data, value);
+    function relay(address target, uint256 value, bytes calldata data) external payable virtual onlyGovernance {
+        (bool success, bytes memory returndata) = target.call{value: value}(data);
+        Address.verifyCallResult(success, returndata, "Governor: relay reverted without message");
     }
 
     /**
@@ -559,12 +595,7 @@ abstract contract Governor is Context, ERC165, EIP712, IGovernor, IERC721Receive
     /**
      * @dev See {IERC721Receiver-onERC721Received}.
      */
-    function onERC721Received(
-        address,
-        address,
-        uint256,
-        bytes memory
-    ) public virtual override returns (bytes4) {
+    function onERC721Received(address, address, uint256, bytes memory) public virtual override returns (bytes4) {
         return this.onERC721Received.selector;
     }
 

contracts/governance/IGovernor.sol

@@ -1,16 +1,17 @@
 // SPDX-License-Identifier: MIT
-// OpenZeppelin Contracts (last updated v4.7.0) (governance/IGovernor.sol)
+// OpenZeppelin Contracts (last updated v4.8.0) (governance/IGovernor.sol)
 
 pragma solidity ^0.8.0;
 
-import "../utils/introspection/ERC165.sol";
+import "../interfaces/IERC165.sol";
+import "../interfaces/IERC6372.sol";
 
 /**
  * @dev Interface of the {Governor} core.
  *
  * _Available since v4.3._
  */
-abstract contract IGovernor is IERC165 {
+abstract contract IGovernor is IERC165, IERC6372 {
     enum ProposalState {
         Pending,
         Active,
@@ -32,8 +33,8 @@ abstract contract IGovernor is IERC165 {
         uint256[] values,
         string[] signatures,
         bytes[] calldatas,
-        uint256 startBlock,
-        uint256 endBlock,
+        uint256 voteStart,
+        uint256 voteEnd,
         string description
     );
 
@@ -58,7 +59,7 @@ abstract contract IGovernor is IERC165 {
      * @dev Emitted when a vote is cast with params.
      *
      * Note: `support` values should be seen as buckets. Their interpretation depends on the voting module used.
-     * `params` are additional encoded parameters. Their intepepretation also depends on the voting module used.
+     * `params` are additional encoded parameters. Their interpepretation also depends on the voting module used.
      */
     event VoteCastWithParams(
         address indexed voter,
@@ -81,6 +82,19 @@ abstract contract IGovernor is IERC165 {
      */
     function version() public view virtual returns (string memory);
 
+    /**
+     * @notice module:core
+     * @dev See {IERC6372}
+     */
+    function clock() public view virtual override returns (uint48);
+
+    /**
+     * @notice module:core
+     * @dev See EIP-6372.
+     */
+    // solhint-disable-next-line func-name-mixedcase
+    function CLOCK_MODE() public view virtual override returns (string memory);
+
     /**
      * @notice module:voting
      * @dev A description of the possible `support` values for {castVote} and the way these votes are counted, meant to
@@ -104,7 +118,7 @@ abstract contract IGovernor is IERC165 {
      * JavaScript class.
      */
     // solhint-disable-next-line func-name-mixedcase
-    function COUNTING_MODE() public pure virtual returns (string memory);
+    function COUNTING_MODE() public view virtual returns (string memory);
 
     /**
      * @notice module:core
@@ -125,29 +139,33 @@ abstract contract IGovernor is IERC165 {
 
     /**
      * @notice module:core
-     * @dev Block number used to retrieve user's votes and quorum. As per Compound's Comp and OpenZeppelin's
-     * ERC20Votes, the snapshot is performed at the end of this block. Hence, voting for this proposal starts at the
-     * beginning of the following block.
+     * @dev Timepoint used to retrieve user's votes and quorum. If using block number (as per Compound's Comp), the
+     * snapshot is performed at the end of this block. Hence, voting for this proposal starts at the beginning of the
+     * following block.
      */
     function proposalSnapshot(uint256 proposalId) public view virtual returns (uint256);
 
     /**
      * @notice module:core
-     * @dev Block number at which votes close. Votes close at the end of this block, so it is possible to cast a vote
-     * during this block.
+     * @dev Timepoint at which votes close. If using block number, votes close at the end of this block, so it is
+     * possible to cast a vote during this block.
      */
     function proposalDeadline(uint256 proposalId) public view virtual returns (uint256);
 
     /**
      * @notice module:user-config
-     * @dev Delay, in number of block, between the proposal is created and the vote starts. This can be increassed to
-     * leave time for users to buy voting power, or delegate it, before the voting of a proposal starts.
+     * @dev Delay, between the proposal is created and the vote starts. The unit this duration is expressed in depends
+     * on the clock (see EIP-6372) this contract uses.
+     *
+     * This can be increased to leave time for users to buy voting power, or delegate it, before the voting of a
+     * proposal starts.
      */
     function votingDelay() public view virtual returns (uint256);
 
     /**
      * @notice module:user-config
-     * @dev Delay, in number of blocks, between the vote start and vote ends.
+     * @dev Delay, between the vote start and vote ends. The unit this duration is expressed in depends on the clock
+     * (see EIP-6372) this contract uses.
      *
      * NOTE: The {votingDelay} can delay the start of the vote. This must be considered when setting the voting
      * duration compared to the voting delay.
@@ -158,27 +176,27 @@ abstract contract IGovernor is IERC165 {
      * @notice module:user-config
      * @dev Minimum number of cast voted required for a proposal to be successful.
      *
-     * Note: The `blockNumber` parameter corresponds to the snapshot used for counting vote. This allows to scale the
-     * quorum depending on values such as the totalSupply of a token at this block (see {ERC20Votes}).
+     * NOTE: The `timepoint` parameter corresponds to the snapshot used for counting vote. This allows to scale the
+     * quorum depending on values such as the totalSupply of a token at this timepoint (see {ERC20Votes}).
      */
-    function quorum(uint256 blockNumber) public view virtual returns (uint256);
+    function quorum(uint256 timepoint) public view virtual returns (uint256);
 
     /**
      * @notice module:reputation
-     * @dev Voting power of an `account` at a specific `blockNumber`.
+     * @dev Voting power of an `account` at a specific `timepoint`.
      *
      * Note: this can be implemented in a number of ways, for example by reading the delegated balance from one (or
      * multiple), {ERC20Votes} tokens.
      */
-    function getVotes(address account, uint256 blockNumber) public view virtual returns (uint256);
+    function getVotes(address account, uint256 timepoint) public view virtual returns (uint256);
 
     /**
      * @notice module:reputation
-     * @dev Voting power of an `account` at a specific `blockNumber` given additional encoded parameters.
+     * @dev Voting power of an `account` at a specific `timepoint` given additional encoded parameters.
      */
     function getVotesWithParams(
         address account,
-        uint256 blockNumber,
+        uint256 timepoint,
         bytes memory params
     ) public view virtual returns (uint256);
 
@@ -189,8 +207,8 @@ abstract contract IGovernor is IERC165 {
     function hasVoted(uint256 proposalId, address account) public view virtual returns (bool);
 
     /**
-     * @dev Create a new proposal. Vote start {IGovernor-votingDelay} blocks after the proposal is created and ends
-     * {IGovernor-votingPeriod} blocks after the voting starts.
+     * @dev Create a new proposal. Vote start after a delay specified by {IGovernor-votingDelay} and lasts for a
+     * duration specified by {IGovernor-votingPeriod}.
      *
      * Emits a {ProposalCreated} event.
      */
@@ -216,6 +234,19 @@ abstract contract IGovernor is IERC165 {
         bytes32 descriptionHash
     ) public payable virtual returns (uint256 proposalId);
 
+    /**
+     * @dev Cancel a proposal. A proposal is cancellable by the proposer, but only while it is Pending state, i.e.
+     * before the vote starts.
+     *
+     * Emits a {ProposalCanceled} event.
+     */
+    function cancel(
+        address[] memory targets,
+        uint256[] memory values,
+        bytes[] memory calldatas,
+        bytes32 descriptionHash
+    ) public virtual returns (uint256 proposalId);
+
     /**
      * @dev Cast a vote
      *

contracts/governance/README.adoc

@@ -20,7 +20,7 @@ For a written walkthrough, check out our guide on xref:ROOT:governance.adoc[How
 
 Votes modules determine the source of voting power, and sometimes quorum number.
 
-* {GovernorVotes}: Extracts voting weight from an {ERC20Votes} token.
+* {GovernorVotes}: Extracts voting weight from an {ERC20Votes}, or since v4.5 an {ERC721Votes} token.
 
 * {GovernorVotesComp}: Extracts voting weight from a COMP-like or {ERC20VotesComp} token.
 
@@ -46,9 +46,9 @@ Other extensions can customize the behavior or interface in multiple ways.
 
 In addition to modules and extensions, the core contract requires a few virtual functions to be implemented to your particular specifications:
 
-* <<Governor-votingDelay-,`votingDelay()`>>: Delay (in number of blocks) since the proposal is submitted until voting power is fixed and voting starts. This can be used to enforce a delay after a proposal is published for users to buy tokens, or delegate their votes.
-* <<Governor-votingPeriod-,`votingPeriod()`>>: Delay (in number of blocks) since the proposal starts until voting ends.
-* <<Governor-quorum-uint256-,`quorum(uint256 blockNumber)`>>: Quorum required for a proposal to be successful. This function includes a `blockNumber` argument so the quorum can adapt through time, for example, to follow a token's `totalSupply`.
+* <<Governor-votingDelay-,`votingDelay()`>>: Delay (in EIP-6372 clock) since the proposal is submitted until voting power is fixed and voting starts. This can be used to enforce a delay after a proposal is published for users to buy tokens, or delegate their votes.
+* <<Governor-votingPeriod-,`votingPeriod()`>>: Delay (in EIP-6372 clock) since the proposal starts until voting ends.
+* <<Governor-quorum-uint256-,`quorum(uint256 timepoint)`>>: Quorum required for a proposal to be successful. This function includes a `timepoint` argument (see EIP-6372) so the quorum can adapt through time, for example, to follow a token's `totalSupply`.
 
 NOTE: Functions of the `Governor` contract do not include access control. If you want to restrict access, you should add these checks by overloading the particular functions. Among these, {Governor-_cancel} is internal by default, and you will have to expose it (with the right access control mechanism) yourself if this function is needed.
 
@@ -153,7 +153,7 @@ Operations status can be queried using the functions:
 [[timelock-admin]]
 ===== Admin
 
-The admins are in charge of managing proposers and executors. For the timelock to be self-governed, this role should only be given to the timelock itself. Upon deployment, both the timelock and the deployer have this role. After further configuration and testing, the deployer can renounce this role such that all further maintenance operations have to go through the timelock process.
+The admins are in charge of managing proposers and executors. For the timelock to be self-governed, this role should only be given to the timelock itself. Upon deployment, the admin role can be granted to any address (in addition to the timelock itself). After further configuration and testing, this optional admin should renounce its role such that all further maintenance operations have to go through the timelock process.
 
 This role is identified by the *TIMELOCK_ADMIN_ROLE* value: `0x5f58e3a2316349923ce3780f8d587db2d72378aed66a8261c916544fa6846ca5`
 

contracts/governance/TimelockController.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-// OpenZeppelin Contracts (last updated v4.7.0) (governance/TimelockController.sol)
+// OpenZeppelin Contracts (last updated v4.8.0) (governance/TimelockController.sol)
 
 pragma solidity ^0.8.0;
 
@@ -51,6 +51,11 @@ contract TimelockController is AccessControl, IERC721Receiver, IERC1155Receiver
      */
     event CallExecuted(bytes32 indexed id, uint256 indexed index, address target, uint256 value, bytes data);
 
+    /**
+     * @dev Emitted when new proposal is scheduled with non-zero salt.
+     */
+    event CallSalt(bytes32 indexed id, bytes32 salt);
+
     /**
      * @dev Emitted when operation `id` is cancelled.
      */
@@ -62,31 +67,32 @@ contract TimelockController is AccessControl, IERC721Receiver, IERC1155Receiver
     event MinDelayChange(uint256 oldDuration, uint256 newDuration);
 
     /**
-     * @dev Initializes the contract with a given `minDelay`, and a list of
-     * initial proposers and executors. The proposers receive both the
-     * proposer and the canceller role (for backward compatibility). The
-     * executors receive the executor role.
+     * @dev Initializes the contract with the following parameters:
      *
-     * NOTE: At construction, both the deployer and the timelock itself are
-     * administrators. This helps further configuration of the timelock by the
-     * deployer. After configuration is done, it is recommended that the
-     * deployer renounces its admin position and relies on timelocked
-     * operations to perform future maintenance.
+     * - `minDelay`: initial minimum delay for operations
+     * - `proposers`: accounts to be granted proposer and canceller roles
+     * - `executors`: accounts to be granted executor role
+     * - `admin`: optional account to be granted admin role; disable with zero address
+     *
+     * IMPORTANT: The optional admin can aid with initial configuration of roles after deployment
+     * without being subject to delay, but this role should be subsequently renounced in favor of
+     * administration through timelocked proposals. Previous versions of this contract would assign
+     * this admin to the deployer automatically and should be renounced as well.
      */
-    constructor(
-        uint256 minDelay,
-        address[] memory proposers,
-        address[] memory executors
-    ) {
+    constructor(uint256 minDelay, address[] memory proposers, address[] memory executors, address admin) {
         _setRoleAdmin(TIMELOCK_ADMIN_ROLE, TIMELOCK_ADMIN_ROLE);
         _setRoleAdmin(PROPOSER_ROLE, TIMELOCK_ADMIN_ROLE);
         _setRoleAdmin(EXECUTOR_ROLE, TIMELOCK_ADMIN_ROLE);
         _setRoleAdmin(CANCELLER_ROLE, TIMELOCK_ADMIN_ROLE);
 
-        // deployer + self administration
-        _setupRole(TIMELOCK_ADMIN_ROLE, _msgSender());
+        // self administration
         _setupRole(TIMELOCK_ADMIN_ROLE, address(this));
 
+        // optional admin
+        if (admin != address(0)) {
+            _setupRole(TIMELOCK_ADMIN_ROLE, admin);
+        }
+
         // register proposers and cancellers
         for (uint256 i = 0; i < proposers.length; ++i) {
             _setupRole(PROPOSER_ROLE, proposers[i]);
@@ -158,7 +164,7 @@ contract TimelockController is AccessControl, IERC721Receiver, IERC1155Receiver
     }
 
     /**
-     * @dev Returns the timestamp at with an operation becomes ready (0 for
+     * @dev Returns the timestamp at which an operation becomes ready (0 for
      * unset operations, 1 for done operations).
      */
     function getTimestamp(bytes32 id) public view virtual returns (uint256 timestamp) {
@@ -205,7 +211,7 @@ contract TimelockController is AccessControl, IERC721Receiver, IERC1155Receiver
     /**
      * @dev Schedule an operation containing a single transaction.
      *
-     * Emits a {CallScheduled} event.
+     * Emits events {CallScheduled} and {CallSalt}.
      *
      * Requirements:
      *
@@ -222,12 +228,15 @@ contract TimelockController is AccessControl, IERC721Receiver, IERC1155Receiver
         bytes32 id = hashOperation(target, value, data, predecessor, salt);
         _schedule(id, delay);
         emit CallScheduled(id, 0, target, value, data, predecessor, delay);
+        if (salt != bytes32(0)) {
+            emit CallSalt(id, salt);
+        }
     }
 
     /**
      * @dev Schedule an operation containing a batch of transactions.
      *
-     * Emits one {CallScheduled} event per transaction in the batch.
+     * Emits a {CallSalt} event and one {CallScheduled} event per transaction in the batch.
      *
      * Requirements:
      *
@@ -249,10 +258,13 @@ contract TimelockController is AccessControl, IERC721Receiver, IERC1155Receiver
         for (uint256 i = 0; i < targets.length; ++i) {
             emit CallScheduled(id, i, targets[i], values[i], payloads[i], predecessor, delay);
         }
+        if (salt != bytes32(0)) {
+            emit CallSalt(id, salt);
+        }
     }
 
     /**
-     * @dev Schedule an operation that is to becomes valid after a given delay.
+     * @dev Schedule an operation that is to become valid after a given delay.
      */
     function _schedule(bytes32 id, uint256 delay) private {
         require(!isOperation(id), "TimelockController: operation already scheduled");
@@ -310,6 +322,9 @@ contract TimelockController is AccessControl, IERC721Receiver, IERC1155Receiver
      *
      * - the caller must have the 'executor' role.
      */
+    // This function can reenter, but it doesn't pose a risk because _afterCall checks that the proposal is pending,
+    // thus any modifications to the operation during reentrancy should be caught.
+    // slither-disable-next-line reentrancy-eth
     function executeBatch(
         address[] calldata targets,
         uint256[] calldata values,
@@ -336,11 +351,7 @@ contract TimelockController is AccessControl, IERC721Receiver, IERC1155Receiver
     /**
      * @dev Execute an operation's call.
      */
-    function _execute(
-        address target,
-        uint256 value,
-        bytes calldata data
-    ) internal virtual {
+    function _execute(address target, uint256 value, bytes calldata data) internal virtual {
         (bool success, ) = target.call{value: value}(data);
         require(success, "TimelockController: underlying transaction reverted");
     }
@@ -380,12 +391,7 @@ contract TimelockController is AccessControl, IERC721Receiver, IERC1155Receiver
     /**
      * @dev See {IERC721Receiver-onERC721Received}.
      */
-    function onERC721Received(
-        address,
-        address,
-        uint256,
-        bytes memory
-    ) public virtual override returns (bytes4) {
+    function onERC721Received(address, address, uint256, bytes memory) public virtual override returns (bytes4) {
         return this.onERC721Received.selector;
     }
 

contracts/governance/compatibility/GovernorCompatibilityBravo.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-// OpenZeppelin Contracts (last updated v4.6.0) (governance/compatibility/GovernorCompatibilityBravo.sol)
+// OpenZeppelin Contracts (last updated v4.8.0) (governance/compatibility/GovernorCompatibilityBravo.sol)
 
 pragma solidity ^0.8.0;
 
@@ -9,10 +9,10 @@ import "../Governor.sol";
 import "./IGovernorCompatibilityBravo.sol";
 
 /**
- * @dev Compatibility layer that implements GovernorBravo compatibility on to of {Governor}.
+ * @dev Compatibility layer that implements GovernorBravo compatibility on top of {Governor}.
  *
  * This compatibility layer includes a voting system and requires a {IGovernorTimelock} compatible module to be added
- * through inheritance. It does not include token bindings, not does it include any variable upgrade patterns.
+ * through inheritance. It does not include token bindings, nor does it include any variable upgrade patterns.
  *
  * NOTE: When using this module, you may need to enable the Solidity optimizer to avoid hitting the contract size limit.
  *
@@ -55,6 +55,7 @@ abstract contract GovernorCompatibilityBravo is IGovernorTimelock, IGovernorComp
         bytes[] memory calldatas,
         string memory description
     ) public virtual override(IGovernor, Governor) returns (uint256) {
+        // Stores the proposal details (if not already present) and executes the propose logic from the core.
         _storeProposal(_msgSender(), targets, values, new string[](calldatas.length), calldatas, description);
         return super.propose(targets, values, calldatas, description);
     }
@@ -69,6 +70,10 @@ abstract contract GovernorCompatibilityBravo is IGovernorTimelock, IGovernorComp
         bytes[] memory calldatas,
         string memory description
     ) public virtual override returns (uint256) {
+        // Stores the full proposal and fallback to the public (possibly overridden) propose. The fallback is done
+        // after the full proposal is stored, so the store operation included in the fallback will be skipped. Here we
+        // call `propose` and not `super.propose` to make sure if a child contract override `propose`, whatever code
+        // is added their is also executed when calling this alternative interface.
         _storeProposal(_msgSender(), targets, values, signatures, calldatas, description);
         return propose(targets, values, _encodeCalldata(signatures, calldatas), description);
     }
@@ -77,52 +82,72 @@ abstract contract GovernorCompatibilityBravo is IGovernorTimelock, IGovernorComp
      * @dev See {IGovernorCompatibilityBravo-queue}.
      */
     function queue(uint256 proposalId) public virtual override {
-        ProposalDetails storage details = _proposalDetails[proposalId];
-        queue(
-            details.targets,
-            details.values,
-            _encodeCalldata(details.signatures, details.calldatas),
-            details.descriptionHash
-        );
+        (
+            address[] memory targets,
+            uint256[] memory values,
+            bytes[] memory calldatas,
+            bytes32 descriptionHash
+        ) = _getProposalParameters(proposalId);
+
+        queue(targets, values, calldatas, descriptionHash);
     }
 
     /**
      * @dev See {IGovernorCompatibilityBravo-execute}.
      */
     function execute(uint256 proposalId) public payable virtual override {
-        ProposalDetails storage details = _proposalDetails[proposalId];
-        execute(
-            details.targets,
-            details.values,
-            _encodeCalldata(details.signatures, details.calldatas),
-            details.descriptionHash
-        );
+        (
+            address[] memory targets,
+            uint256[] memory values,
+            bytes[] memory calldatas,
+            bytes32 descriptionHash
+        ) = _getProposalParameters(proposalId);
+
+        execute(targets, values, calldatas, descriptionHash);
     }
 
-    function cancel(uint256 proposalId) public virtual override {
-        ProposalDetails storage details = _proposalDetails[proposalId];
+    /**
+     * @dev Cancel a proposal with GovernorBravo logic.
+     */
+    function cancel(uint256 proposalId) public virtual {
+        (
+            address[] memory targets,
+            uint256[] memory values,
+            bytes[] memory calldatas,
+            bytes32 descriptionHash
+        ) = _getProposalParameters(proposalId);
+
+        cancel(targets, values, calldatas, descriptionHash);
+    }
+
+    /**
+     * @dev Cancel a proposal with GovernorBravo logic. At any moment a proposal can be cancelled, either by the
+     * proposer, or by third parties if the proposer's voting power has dropped below the proposal threshold.
+     */
+    function cancel(
+        address[] memory targets,
+        uint256[] memory values,
+        bytes[] memory calldatas,
+        bytes32 descriptionHash
+    ) public virtual override(IGovernor, Governor) returns (uint256) {
+        uint256 proposalId = hashProposal(targets, values, calldatas, descriptionHash);
+        address proposer = _proposalDetails[proposalId].proposer;
 
         require(
-            _msgSender() == details.proposer || getVotes(details.proposer, block.number - 1) < proposalThreshold(),
+            _msgSender() == proposer || getVotes(proposer, clock() - 1) < proposalThreshold(),
             "GovernorBravo: proposer above threshold"
         );
 
-        _cancel(
-            details.targets,
-            details.values,
-            _encodeCalldata(details.signatures, details.calldatas),
-            details.descriptionHash
-        );
+        return _cancel(targets, values, calldatas, descriptionHash);
     }
 
     /**
      * @dev Encodes calldatas with optional function signature.
      */
-    function _encodeCalldata(string[] memory signatures, bytes[] memory calldatas)
-        private
-        pure
-        returns (bytes[] memory)
-    {
+    function _encodeCalldata(
+        string[] memory signatures,
+        bytes[] memory calldatas
+    ) private pure returns (bytes[] memory) {
         bytes[] memory fullcalldatas = new bytes[](calldatas.length);
 
         for (uint256 i = 0; i < signatures.length; ++i) {
@@ -135,7 +160,26 @@ abstract contract GovernorCompatibilityBravo is IGovernorTimelock, IGovernorComp
     }
 
     /**
-     * @dev Store proposal metadata for later lookup
+     * @dev Retrieve proposal parameters by id, with fully encoded calldatas.
+     */
+    function _getProposalParameters(
+        uint256 proposalId
+    )
+        private
+        view
+        returns (address[] memory targets, uint256[] memory values, bytes[] memory calldatas, bytes32 descriptionHash)
+    {
+        ProposalDetails storage details = _proposalDetails[proposalId];
+        return (
+            details.targets,
+            details.values,
+            _encodeCalldata(details.signatures, details.calldatas),
+            details.descriptionHash
+        );
+    }
+
+    /**
+     * @dev Store proposal metadata (if not already present) for later lookup.
      */
     function _storeProposal(
         address proposer,
@@ -163,7 +207,9 @@ abstract contract GovernorCompatibilityBravo is IGovernorTimelock, IGovernorComp
     /**
      * @dev See {IGovernorCompatibilityBravo-proposals}.
      */
-    function proposals(uint256 proposalId)
+    function proposals(
+        uint256 proposalId
+    )
         public
         view
         virtual
@@ -200,7 +246,9 @@ abstract contract GovernorCompatibilityBravo is IGovernorTimelock, IGovernorComp
     /**
      * @dev See {IGovernorCompatibilityBravo-getActions}.
      */
-    function getActions(uint256 proposalId)
+    function getActions(
+        uint256 proposalId
+    )
         public
         view
         virtual
@@ -227,7 +275,7 @@ abstract contract GovernorCompatibilityBravo is IGovernorTimelock, IGovernorComp
      * @dev See {IGovernorCompatibilityBravo-quorumVotes}.
      */
     function quorumVotes() public view virtual override returns (uint256) {
-        return quorum(block.number - 1);
+        return quorum(clock() - 1);
     }
 
     // ==================================================== Voting ====================================================
@@ -247,7 +295,7 @@ abstract contract GovernorCompatibilityBravo is IGovernorTimelock, IGovernorComp
     }
 
     /**
-     * @dev See {Governor-_voteSucceeded}. In this module, the forVotes must be scritly over the againstVotes.
+     * @dev See {Governor-_voteSucceeded}. In this module, the forVotes must be strictly over the againstVotes.
      */
     function _voteSucceeded(uint256 proposalId) internal view virtual override returns (bool) {
         ProposalDetails storage details = _proposalDetails[proposalId];

contracts/governance/compatibility/IGovernorCompatibilityBravo.sol

@@ -50,7 +50,9 @@ abstract contract IGovernorCompatibilityBravo is IGovernor {
     /**
      * @dev Part of the Governor Bravo's interface: _"The official record of all proposals ever proposed"_.
      */
-    function proposals(uint256)
+    function proposals(
+        uint256
+    )
         public
         view
         virtual
@@ -88,15 +90,12 @@ abstract contract IGovernorCompatibilityBravo is IGovernor {
      */
     function execute(uint256 proposalId) public payable virtual;
 
-    /**
-     * @dev Cancels a proposal only if sender is the proposer, or proposer delegates dropped below proposal threshold.
-     */
-    function cancel(uint256 proposalId) public virtual;
-
     /**
      * @dev Part of the Governor Bravo's interface: _"Gets actions of a proposal"_.
      */
-    function getActions(uint256 proposalId)
+    function getActions(
+        uint256 proposalId
+    )
         public
         view
         virtual

contracts/governance/extensions/GovernorCountingSimple.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-// OpenZeppelin Contracts (last updated v4.6.0) (governance/extensions/GovernorCountingSimple.sol)
+// OpenZeppelin Contracts (last updated v4.8.0) (governance/extensions/GovernorCountingSimple.sol)
 
 pragma solidity ^0.8.0;
 
@@ -47,16 +47,9 @@ abstract contract GovernorCountingSimple is Governor {
     /**
      * @dev Accessor to the internal vote counts.
      */
-    function proposalVotes(uint256 proposalId)
-        public
-        view
-        virtual
-        returns (
-            uint256 againstVotes,
-            uint256 forVotes,
-            uint256 abstainVotes
-        )
-    {
+    function proposalVotes(
+        uint256 proposalId
+    ) public view virtual returns (uint256 againstVotes, uint256 forVotes, uint256 abstainVotes) {
         ProposalVote storage proposalVote = _proposalVotes[proposalId];
         return (proposalVote.againstVotes, proposalVote.forVotes, proposalVote.abstainVotes);
     }

contracts/governance/extensions/GovernorPreventLateQuorum.sol

@@ -19,10 +19,11 @@ import "../../utils/math/Math.sol";
  */
 abstract contract GovernorPreventLateQuorum is Governor {
     using SafeCast for uint256;
-    using Timers for Timers.BlockNumber;
 
     uint64 private _voteExtension;
-    mapping(uint256 => Timers.BlockNumber) private _extendedDeadlines;
+
+    /// @custom:oz-retyped-from mapping(uint256 => Timers.BlockNumber)
+    mapping(uint256 => uint64) private _extendedDeadlines;
 
     /// @dev Emitted when a proposal deadline is pushed back due to reaching quorum late in its voting period.
     event ProposalExtended(uint256 indexed proposalId, uint64 extendedDeadline);
@@ -44,7 +45,7 @@ abstract contract GovernorPreventLateQuorum is Governor {
      * proposal reached quorum late in the voting period. See {Governor-proposalDeadline}.
      */
     function proposalDeadline(uint256 proposalId) public view virtual override returns (uint256) {
-        return Math.max(super.proposalDeadline(proposalId), _extendedDeadlines[proposalId].getDeadline());
+        return Math.max(super.proposalDeadline(proposalId), _extendedDeadlines[proposalId]);
     }
 
     /**
@@ -62,16 +63,14 @@ abstract contract GovernorPreventLateQuorum is Governor {
     ) internal virtual override returns (uint256) {
         uint256 result = super._castVote(proposalId, account, support, reason, params);
 
-        Timers.BlockNumber storage extendedDeadline = _extendedDeadlines[proposalId];
-
-        if (extendedDeadline.isUnset() && _quorumReached(proposalId)) {
-            uint64 extendedDeadlineValue = block.number.toUint64() + lateQuorumVoteExtension();
+        if (_extendedDeadlines[proposalId] == 0 && _quorumReached(proposalId)) {
+            uint64 extendedDeadline = clock() + lateQuorumVoteExtension();
 
-            if (extendedDeadlineValue > proposalDeadline(proposalId)) {
-                emit ProposalExtended(proposalId, extendedDeadlineValue);
+            if (extendedDeadline > proposalDeadline(proposalId)) {
+                emit ProposalExtended(proposalId, extendedDeadline);
             }
 
-            extendedDeadline.setDeadline(extendedDeadlineValue);
+            _extendedDeadlines[proposalId] = extendedDeadline;
         }
 
         return result;

contracts/governance/extensions/GovernorSettings.sol

@@ -22,11 +22,7 @@ abstract contract GovernorSettings is Governor {
     /**
      * @dev Initialize the governance parameters.
      */
-    constructor(
-        uint256 initialVotingDelay,
-        uint256 initialVotingPeriod,
-        uint256 initialProposalThreshold
-    ) {
+    constructor(uint256 initialVotingDelay, uint256 initialVotingPeriod, uint256 initialProposalThreshold) {
         _setVotingDelay(initialVotingDelay);
         _setVotingPeriod(initialVotingPeriod);
         _setProposalThreshold(initialProposalThreshold);

contracts/governance/extensions/GovernorTimelockCompound.sol

@@ -22,15 +22,11 @@ import "../../vendor/compound/ICompoundTimelock.sol";
  */
 abstract contract GovernorTimelockCompound is IGovernorTimelock, Governor {
     using SafeCast for uint256;
-    using Timers for Timers.Timestamp;
-
-    struct ProposalTimelock {
-        Timers.Timestamp timer;
-    }
 
     ICompoundTimelock private _timelock;
 
-    mapping(uint256 => ProposalTimelock) private _proposalTimelocks;
+    /// @custom:oz-retyped-from mapping(uint256 => GovernorTimelockCompound.ProposalTimelock)
+    mapping(uint256 => uint64) private _proposalTimelocks;
 
     /**
      * @dev Emitted when the timelock controller used for proposal execution is modified.
@@ -82,7 +78,7 @@ abstract contract GovernorTimelockCompound is IGovernorTimelock, Governor {
      * @dev Public accessor to check the eta of a queued proposal
      */
     function proposalEta(uint256 proposalId) public view virtual override returns (uint256) {
-        return _proposalTimelocks[proposalId].timer.getDeadline();
+        return _proposalTimelocks[proposalId];
     }
 
     /**
@@ -99,7 +95,8 @@ abstract contract GovernorTimelockCompound is IGovernorTimelock, Governor {
         require(state(proposalId) == ProposalState.Succeeded, "Governor: proposal not successful");
 
         uint256 eta = block.timestamp + _timelock.delay();
-        _proposalTimelocks[proposalId].timer.setDeadline(eta.toUint64());
+        _proposalTimelocks[proposalId] = eta.toUint64();
+
         for (uint256 i = 0; i < targets.length; ++i) {
             require(
                 !_timelock.queuedTransactions(keccak256(abi.encode(targets[i], values[i], "", calldatas[i], eta))),
@@ -145,10 +142,12 @@ abstract contract GovernorTimelockCompound is IGovernorTimelock, Governor {
 
         uint256 eta = proposalEta(proposalId);
         if (eta > 0) {
+            // update state first
+            delete _proposalTimelocks[proposalId];
+            // do external call later
             for (uint256 i = 0; i < targets.length; ++i) {
                 _timelock.cancelTransaction(targets[i], values[i], "", calldatas[i], eta);
             }
-            _proposalTimelocks[proposalId].timer.reset();
         }
 
         return proposalId;

contracts/governance/extensions/GovernorTimelockControl.sol

@@ -110,7 +110,7 @@ abstract contract GovernorTimelockControl is IGovernorTimelock, Governor {
      * @dev Overridden execute function that run the already queued proposal through the timelock.
      */
     function _execute(
-        uint256, /* proposalId */
+        uint256 /* proposalId */,
         address[] memory targets,
         uint256[] memory values,
         bytes[] memory calldatas,

contracts/governance/extensions/GovernorVotes.sol

@@ -4,7 +4,7 @@
 pragma solidity ^0.8.0;
 
 import "../Governor.sol";
-import "../utils/IVotes.sol";
+import "../../interfaces/IERC5805.sol";
 
 /**
  * @dev Extension of {Governor} for voting weight extraction from an {ERC20Votes} token, or since v4.5 an {ERC721Votes} token.
@@ -12,10 +12,34 @@ import "../utils/IVotes.sol";
  * _Available since v4.3._
  */
 abstract contract GovernorVotes is Governor {
-    IVotes public immutable token;
+    IERC5805 public immutable token;
 
     constructor(IVotes tokenAddress) {
-        token = tokenAddress;
+        token = IERC5805(address(tokenAddress));
+    }
+
+    /**
+     * @dev Clock (as specified in EIP-6372) is set to match the token's clock. Fallback to block numbers if the token
+     * does not implement EIP-6372.
+     */
+    function clock() public view virtual override returns (uint48) {
+        try token.clock() returns (uint48 timepoint) {
+            return timepoint;
+        } catch {
+            return SafeCast.toUint48(block.number);
+        }
+    }
+
+    /**
+     * @dev Machine-readable description of the clock as specified in EIP-6372.
+     */
+    // solhint-disable-next-line func-name-mixedcase
+    function CLOCK_MODE() public view virtual override returns (string memory) {
+        try token.CLOCK_MODE() returns (string memory clockmode) {
+            return clockmode;
+        } catch {
+            return "mode=blocknumber&from=default";
+        }
     }
 
     /**
@@ -23,9 +47,9 @@ abstract contract GovernorVotes is Governor {
      */
     function _getVotes(
         address account,
-        uint256 blockNumber,
+        uint256 timepoint,
         bytes memory /*params*/
     ) internal view virtual override returns (uint256) {
-        return token.getPastVotes(account, blockNumber);
+        return token.getPastVotes(account, timepoint);
     }
 }

contracts/governance/extensions/GovernorVotesComp.sol

@@ -19,13 +19,37 @@ abstract contract GovernorVotesComp is Governor {
     }
 
     /**
-     * Read the voting weight from the token's built in snapshot mechanism (see {Governor-_getVotes}).
+     * @dev Clock (as specified in EIP-6372) is set to match the token's clock. Fallback to block numbers if the token
+     * does not implement EIP-6372.
+     */
+    function clock() public view virtual override returns (uint48) {
+        try token.clock() returns (uint48 timepoint) {
+            return timepoint;
+        } catch {
+            return SafeCast.toUint48(block.number);
+        }
+    }
+
+    /**
+     * @dev Machine-readable description of the clock as specified in EIP-6372.
+     */
+    // solhint-disable-next-line func-name-mixedcase
+    function CLOCK_MODE() public view virtual override returns (string memory) {
+        try token.CLOCK_MODE() returns (string memory clockmode) {
+            return clockmode;
+        } catch {
+            return "mode=blocknumber&from=default";
+        }
+    }
+
+    /**
+     * Read the voting weight from the token's built-in snapshot mechanism (see {Governor-_getVotes}).
      */
     function _getVotes(
         address account,
-        uint256 blockNumber,
+        uint256 timepoint,
         bytes memory /*params*/
     ) internal view virtual override returns (uint256) {
-        return token.getPriorVotes(account, blockNumber);
+        return token.getPriorVotes(account, timepoint);
     }
 }

contracts/governance/extensions/GovernorVotesQuorumFraction.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: MIT
-// OpenZeppelin Contracts (last updated v4.5.0) (governance/extensions/GovernorVotesQuorumFraction.sol)
+// OpenZeppelin Contracts (last updated v4.8.0) (governance/extensions/GovernorVotesQuorumFraction.sol)
 
 pragma solidity ^0.8.0;
 
@@ -14,10 +14,13 @@ import "../../utils/math/SafeCast.sol";
  * _Available since v4.3._
  */
 abstract contract GovernorVotesQuorumFraction is GovernorVotes {
-    using Checkpoints for Checkpoints.History;
+    using SafeCast for *;
+    using Checkpoints for Checkpoints.Trace224;
 
-    uint256 private _quorumNumerator; // DEPRECATED
-    Checkpoints.History private _quorumNumeratorHistory;
+    uint256 private _quorumNumerator; // DEPRECATED in favor of _quorumNumeratorHistory
+
+    /// @custom:oz-retyped-from Checkpoints.History
+    Checkpoints.Trace224 private _quorumNumeratorHistory;
 
     event QuorumNumeratorUpdated(uint256 oldQuorumNumerator, uint256 newQuorumNumerator);
 
@@ -40,9 +43,9 @@ abstract contract GovernorVotesQuorumFraction is GovernorVotes {
     }
 
     /**
-     * @dev Returns the quorum numerator at a specific block number. See {quorumDenominator}.
+     * @dev Returns the quorum numerator at a specific timepoint. See {quorumDenominator}.
      */
-    function quorumNumerator(uint256 blockNumber) public view virtual returns (uint256) {
+    function quorumNumerator(uint256 timepoint) public view virtual returns (uint256) {
         // If history is empty, fallback to old storage
         uint256 length = _quorumNumeratorHistory._checkpoints.length;
         if (length == 0) {
@@ -50,13 +53,13 @@ abstract contract GovernorVotesQuorumFraction is GovernorVotes {
         }
 
         // Optimistic search, check the latest checkpoint
-        Checkpoints.Checkpoint memory latest = _quorumNumeratorHistory._checkpoints[length - 1];
-        if (latest._blockNumber <= blockNumber) {
+        Checkpoints.Checkpoint224 memory latest = _quorumNumeratorHistory._checkpoints[length - 1];
+        if (latest._key <= timepoint) {
             return latest._value;
         }
 
         // Otherwise, do the binary search
-        return _quorumNumeratorHistory.getAtBlock(blockNumber);
+        return _quorumNumeratorHistory.upperLookupRecent(timepoint.toUint32());
     }
 
     /**
@@ -67,10 +70,10 @@ abstract contract GovernorVotesQuorumFraction is GovernorVotes {
     }
 
     /**
-     * @dev Returns the quorum for a block number, in terms of number of votes: `supply * numerator / denominator`.
+     * @dev Returns the quorum for a timepoint, in terms of number of votes: `supply * numerator / denominator`.
      */
-    function quorum(uint256 blockNumber) public view virtual override returns (uint256) {
-        return (token.getPastTotalSupply(blockNumber) * quorumNumerator(blockNumber)) / quorumDenominator();
+    function quorum(uint256 timepoint) public view virtual override returns (uint256) {
+        return (token.getPastTotalSupply(timepoint) * quorumNumerator(timepoint)) / quorumDenominator();
     }
 
     /**
@@ -107,12 +110,12 @@ abstract contract GovernorVotesQuorumFraction is GovernorVotes {
         // Make sure we keep track of the original numerator in contracts upgraded from a version without checkpoints.
         if (oldQuorumNumerator != 0 && _quorumNumeratorHistory._checkpoints.length == 0) {
             _quorumNumeratorHistory._checkpoints.push(
-                Checkpoints.Checkpoint({_blockNumber: 0, _value: SafeCast.toUint224(oldQuorumNumerator)})
+                Checkpoints.Checkpoint224({_key: 0, _value: oldQuorumNumerator.toUint224()})
             );
         }
 
         // Set new quorum for future proposals
-        _quorumNumeratorHistory.push(newQuorumNumerator);
+        _quorumNumeratorHistory.push(clock().toUint32(), newQuorumNumerator.toUint224());
 
         emit QuorumNumeratorUpdated(oldQuorumNumerator, newQuorumNumerator);
     }

contracts/governance/utils/IVotes.sol

@@ -24,18 +24,20 @@ interface IVotes {
     function getVotes(address account) external view returns (uint256);
 
     /**
-     * @dev Returns the amount of votes that `account` had at the end of a past block (`blockNumber`).
+     * @dev Returns the amount of votes that `account` had at a specific moment in the past. If the `clock()` is
+     * configured to use block numbers, this will return the value the end of the corresponding block.
      */
-    function getPastVotes(address account, uint256 blockNumber) external view returns (uint256);
+    function getPastVotes(address account, uint256 timepoint) external view returns (uint256);
 
     /**
-     * @dev Returns the total supply of votes available at the end of a past block (`blockNumber`).
+     * @dev Returns the total supply of votes available at a specific moment in the past. If the `clock()` is
+     * configured to use block numbers, this will return the value the end of the corresponding block.
      *
      * NOTE: This value is the sum of all available votes, which is not necessarily the sum of all delegated votes.
      * Votes that have not been delegated are still part of total supply, even though they would not participate in a
      * vote.
      */
-    function getPastTotalSupply(uint256 blockNumber) external view returns (uint256);
+    function getPastTotalSupply(uint256 timepoint) external view returns (uint256);
 
     /**
      * @dev Returns the delegate that `account` has chosen.
@@ -50,12 +52,5 @@ interface IVotes {
     /**
      * @dev Delegates votes from signer to `delegatee`.
      */
-    function delegateBySig(
-        address delegatee,
-        uint256 nonce,
-        uint256 expiry,
-        uint8 v,
-        bytes32 r,
-        bytes32 s
-    ) external;
+    function delegateBySig(address delegatee, uint256 nonce, uint256 expiry, uint8 v, bytes32 r, bytes32 s) external;
 }

contracts/governance/utils/Votes.sol

@@ -1,12 +1,12 @@
 // SPDX-License-Identifier: MIT
-// OpenZeppelin Contracts (last updated v4.6.0) (governance/utils/Votes.sol)
+// OpenZeppelin Contracts (last updated v4.8.0) (governance/utils/Votes.sol)
 pragma solidity ^0.8.0;
 
+import "../../interfaces/IERC5805.sol";
 import "../../utils/Context.sol";
 import "../../utils/Counters.sol";
 import "../../utils/Checkpoints.sol";
 import "../../utils/cryptography/EIP712.sol";
-import "./IVotes.sol";
 
 /**
  * @dev This is a base abstract contract that tracks voting units, which are a measure of voting power that can be
@@ -28,19 +28,41 @@ import "./IVotes.sol";
  *
  * _Available since v4.5._
  */
-abstract contract Votes is IVotes, Context, EIP712 {
-    using Checkpoints for Checkpoints.History;
+abstract contract Votes is Context, EIP712, IERC5805 {
+    using Checkpoints for Checkpoints.Trace224;
     using Counters for Counters.Counter;
 
     bytes32 private constant _DELEGATION_TYPEHASH =
         keccak256("Delegation(address delegatee,uint256 nonce,uint256 expiry)");
 
     mapping(address => address) private _delegation;
-    mapping(address => Checkpoints.History) private _delegateCheckpoints;
-    Checkpoints.History private _totalCheckpoints;
+
+    /// @custom:oz-retyped-from mapping(address => Checkpoints.History)
+    mapping(address => Checkpoints.Trace224) private _delegateCheckpoints;
+
+    /// @custom:oz-retyped-from Checkpoints.History
+    Checkpoints.Trace224 private _totalCheckpoints;
 
     mapping(address => Counters.Counter) private _nonces;
 
+    /**
+     * @dev Clock used for flagging checkpoints. Can be overridden to implement timestamp based
+     * checkpoints (and voting), in which case {CLOCK_MODE} should be overridden as well to match.
+     */
+    function clock() public view virtual override returns (uint48) {
+        return SafeCast.toUint48(block.number);
+    }
+
+    /**
+     * @dev Machine-readable description of the clock as specified in EIP-6372.
+     */
+    // solhint-disable-next-line func-name-mixedcase
+    function CLOCK_MODE() public view virtual override returns (string memory) {
+        // Check that the clock was not modified
+        require(clock() == block.number);
+        return "mode=blocknumber&from=default";
+    }
+
     /**
      * @dev Returns the current amount of votes that `account` has.
      */
@@ -49,18 +71,21 @@ abstract contract Votes is IVotes, Context, EIP712 {
     }
 
     /**
-     * @dev Returns the amount of votes that `account` had at the end of a past block (`blockNumber`).
+     * @dev Returns the amount of votes that `account` had at a specific moment in the past. If the `clock()` is
+     * configured to use block numbers, this will return the value the end of the corresponding block.
      *
      * Requirements:
      *
-     * - `blockNumber` must have been already mined
+     * - `timepoint` must be in the past. If operating using block numbers, the block must be already mined.
      */
-    function getPastVotes(address account, uint256 blockNumber) public view virtual override returns (uint256) {
-        return _delegateCheckpoints[account].getAtProbablyRecentBlock(blockNumber);
+    function getPastVotes(address account, uint256 timepoint) public view virtual override returns (uint256) {
+        require(timepoint < clock(), "Votes: future lookup");
+        return _delegateCheckpoints[account].upperLookupRecent(SafeCast.toUint32(timepoint));
     }
 
     /**
-     * @dev Returns the total supply of votes available at the end of a past block (`blockNumber`).
+     * @dev Returns the total supply of votes available at a specific moment in the past. If the `clock()` is
+     * configured to use block numbers, this will return the value the end of the corresponding block.
      *
      * NOTE: This value is the sum of all available votes, which is not necessarily the sum of all delegated votes.
      * Votes that have not been delegated are still part of total supply, even though they would not participate in a
@@ -68,11 +93,11 @@ abstract contract Votes is IVotes, Context, EIP712 {
      *
      * Requirements:
      *
-     * - `blockNumber` must have been already mined
+     * - `timepoint` must be in the past. If operating using block numbers, the block must be already mined.
      */
-    function getPastTotalSupply(uint256 blockNumber) public view virtual override returns (uint256) {
-        require(blockNumber < block.number, "Votes: block not yet mined");
-        return _totalCheckpoints.getAtProbablyRecentBlock(blockNumber);
+    function getPastTotalSupply(uint256 timepoint) public view virtual override returns (uint256) {
+        require(timepoint < clock(), "Votes: future lookup");
+        return _totalCheckpoints.upperLookupRecent(SafeCast.toUint32(timepoint));
     }
 
     /**
@@ -122,7 +147,7 @@ abstract contract Votes is IVotes, Context, EIP712 {
     /**
      * @dev Delegate all of `account`'s voting units to `delegatee`.
      *
-     * Emits events {DelegateChanged} and {DelegateVotesChanged}.
+     * Emits events {IVotes-DelegateChanged} and {IVotes-DelegateVotesChanged}.
      */
     function _delegate(address account, address delegatee) internal virtual {
         address oldDelegate = delegates(account);
@@ -136,16 +161,12 @@ abstract contract Votes is IVotes, Context, EIP712 {
      * @dev Transfers, mints, or burns voting units. To register a mint, `from` should be zero. To register a burn, `to`
      * should be zero. Total supply of voting units will be adjusted with mints and burns.
      */
-    function _transferVotingUnits(
-        address from,
-        address to,
-        uint256 amount
-    ) internal virtual {
+    function _transferVotingUnits(address from, address to, uint256 amount) internal virtual {
         if (from == address(0)) {
-            _totalCheckpoints.push(_add, amount);
+            _push(_totalCheckpoints, _add, SafeCast.toUint224(amount));
         }
         if (to == address(0)) {
-            _totalCheckpoints.push(_subtract, amount);
+            _push(_totalCheckpoints, _subtract, SafeCast.toUint224(amount));
         }
         _moveDelegateVotes(delegates(from), delegates(to), amount);
     }
@@ -153,28 +174,40 @@ abstract contract Votes is IVotes, Context, EIP712 {
     /**
      * @dev Moves delegated votes from one delegate to another.
      */
-    function _moveDelegateVotes(
-        address from,
-        address to,
-        uint256 amount
-    ) private {
+    function _moveDelegateVotes(address from, address to, uint256 amount) private {
         if (from != to && amount > 0) {
             if (from != address(0)) {
-                (uint256 oldValue, uint256 newValue) = _delegateCheckpoints[from].push(_subtract, amount);
+                (uint256 oldValue, uint256 newValue) = _push(
+                    _delegateCheckpoints[from],
+                    _subtract,
+                    SafeCast.toUint224(amount)
+                );
                 emit DelegateVotesChanged(from, oldValue, newValue);
             }
             if (to != address(0)) {
-                (uint256 oldValue, uint256 newValue) = _delegateCheckpoints[to].push(_add, amount);
+                (uint256 oldValue, uint256 newValue) = _push(
+                    _delegateCheckpoints[to],
+                    _add,
+                    SafeCast.toUint224(amount)
+                );
                 emit DelegateVotesChanged(to, oldValue, newValue);
             }
         }
     }
 
-    function _add(uint256 a, uint256 b) private pure returns (uint256) {
+    function _push(
+        Checkpoints.Trace224 storage store,
+        function(uint224, uint224) view returns (uint224) op,
+        uint224 delta
+    ) private returns (uint224, uint224) {
+        return store.push(SafeCast.toUint32(clock()), op(store.latest(), delta));
+    }
+
+    function _add(uint224 a, uint224 b) private pure returns (uint224) {
         return a + b;
     }
 
-    function _subtract(uint256 a, uint256 b) private pure returns (uint256) {
+    function _subtract(uint224 a, uint224 b) private pure returns (uint224) {
         return a - b;
     }
 

contracts/interfaces/IERC1363.sol

@@ -6,19 +6,21 @@ pragma solidity ^0.8.0;
 import "./IERC20.sol";
 import "./IERC165.sol";
 
+/**
+ * @dev Interface of an ERC1363 compliant contract, as defined in the
+ * https://eips.ethereum.org/EIPS/eip-1363[EIP].
+ *
+ * Defines a interface for ERC20 tokens that supports executing recipient
+ * code after `transfer` or `transferFrom`, or spender code after `approve`.
+ */
 interface IERC1363 is IERC165, IERC20 {
     /*
-     * Note: the ERC-165 identifier for this interface is 0x4bbee2df.
-     * 0x4bbee2df ===
+     * Note: the ERC-165 identifier for this interface is 0xb0202a11.
+     * 0xb0202a11 ===
      *   bytes4(keccak256('transferAndCall(address,uint256)')) ^
      *   bytes4(keccak256('transferAndCall(address,uint256,bytes)')) ^
      *   bytes4(keccak256('transferFromAndCall(address,address,uint256)')) ^
-     *   bytes4(keccak256('transferFromAndCall(address,address,uint256,bytes)'))
-     */
-
-    /*
-     * Note: the ERC-165 identifier for this interface is 0xfb9ec8ce.
-     * 0xfb9ec8ce ===
+     *   bytes4(keccak256('transferFromAndCall(address,address,uint256,bytes)')) ^
      *   bytes4(keccak256('approveAndCall(address,uint256)')) ^
      *   bytes4(keccak256('approveAndCall(address,uint256,bytes)'))
      */
@@ -26,70 +28,53 @@ interface IERC1363 is IERC165, IERC20 {
     /**
      * @dev Transfer tokens from `msg.sender` to another address and then call `onTransferReceived` on receiver
      * @param to address The address which you want to transfer to
-     * @param value uint256 The amount of tokens to be transferred
+     * @param amount uint256 The amount of tokens to be transferred
      * @return true unless throwing
      */
-    function transferAndCall(address to, uint256 value) external returns (bool);
+    function transferAndCall(address to, uint256 amount) external returns (bool);
 
     /**
      * @dev Transfer tokens from `msg.sender` to another address and then call `onTransferReceived` on receiver
      * @param to address The address which you want to transfer to
-     * @param value uint256 The amount of tokens to be transferred
+     * @param amount uint256 The amount of tokens to be transferred
      * @param data bytes Additional data with no specified format, sent in call to `to`
      * @return true unless throwing
      */
-    function transferAndCall(
-        address to,
-        uint256 value,
-        bytes memory data
-    ) external returns (bool);
+    function transferAndCall(address to, uint256 amount, bytes memory data) external returns (bool);
 
     /**
      * @dev Transfer tokens from one address to another and then call `onTransferReceived` on receiver
      * @param from address The address which you want to send tokens from
      * @param to address The address which you want to transfer to
-     * @param value uint256 The amount of tokens to be transferred
+     * @param amount uint256 The amount of tokens to be transferred
      * @return true unless throwing
      */
-    function transferFromAndCall(
-        address from,
-        address to,
-        uint256 value
-    ) external returns (bool);
+    function transferFromAndCall(address from, address to, uint256 amount) external returns (bool);
 
     /**
      * @dev Transfer tokens from one address to another and then call `onTransferReceived` on receiver
      * @param from address The address which you want to send tokens from
      * @param to address The address which you want to transfer to
-     * @param value uint256 The amount of tokens to be transferred
+     * @param amount uint256 The amount of tokens to be transferred
      * @param data bytes Additional data with no specified format, sent in call to `to`
      * @return true unless throwing
      */
-    function transferFromAndCall(
-        address from,
-        address to,
-        uint256 value,
-        bytes memory data
-    ) external returns (bool);
+    function transferFromAndCall(address from, address to, uint256 amount, bytes memory data) external returns (bool);
 
     /**
      * @dev Approve the passed address to spend the specified amount of tokens on behalf of msg.sender
      * and then call `onApprovalReceived` on spender.
      * @param spender address The address which will spend the funds
-     * @param value uint256 The amount of tokens to be spent
+     * @param amount uint256 The amount of tokens to be spent
      */
-    function approveAndCall(address spender, uint256 value) external returns (bool);
+    function approveAndCall(address spender, uint256 amount) external returns (bool);
 
     /**
      * @dev Approve the passed address to spend the specified amount of tokens on behalf of msg.sender
      * and then call `onApprovalReceived` on spender.
      * @param spender address The address which will spend the funds
-     * @param value uint256 The amount of tokens to be spent
+     * @param amount uint256 The amount of tokens to be spent
      * @param data bytes Additional data with no specified format, sent in call to `spender`
      */
-    function approveAndCall(
-        address spender,
-        uint256 value,
-        bytes memory data
-    ) external returns (bool);
+    function approveAndCall(address spender, uint256 amount, bytes memory data) external returns (bool);
 }

contracts/interfaces/IERC1363Receiver.sol

@@ -3,6 +3,10 @@
 
 pragma solidity ^0.8.0;
 
+/**
+ * @dev Interface for any contract that wants to support {IERC1363-transferAndCall}
+ * or {IERC1363-transferFromAndCall} from {ERC1363} token contracts.
+ */
 interface IERC1363Receiver {
     /*
      * Note: the ERC-165 identifier for this interface is 0x88a7ca5c.
@@ -18,15 +22,14 @@ interface IERC1363Receiver {
      * Note: the token contract address is always the message sender.
      * @param operator address The address which called `transferAndCall` or `transferFromAndCall` function
      * @param from address The address which are token transferred from
-     * @param value uint256 The amount of tokens transferred
+     * @param amount uint256 The amount of tokens transferred
      * @param data bytes Additional data with no specified format
-     * @return `bytes4(keccak256("onTransferReceived(address,address,uint256,bytes)"))`
-     *  unless throwing
+     * @return `bytes4(keccak256("onTransferReceived(address,address,uint256,bytes)"))` unless throwing
      */
     function onTransferReceived(
         address operator,
         address from,
-        uint256 value,
+        uint256 amount,
         bytes memory data
     ) external returns (bytes4);
 }