diff --git a/les/handler.go b/les/handler.go
index 19ccbcd2b6..2fb2067dd1 100644
--- a/les/handler.go
+++ b/les/handler.go
@@ -324,7 +324,11 @@ func (pm *ProtocolManager) handle(p *peer) error {
 	}
 }
 
-var reqList = []uint64{GetBlockHeadersMsg, GetBlockBodiesMsg, GetCodeMsg, GetReceiptsMsg, GetProofsV1Msg, SendTxMsg, SendTxV2Msg, GetTxStatusMsg, GetHeaderProofsMsg, GetProofsV2Msg, GetHelperTrieProofsMsg}
+var (
+	reqList   = []uint64{GetBlockHeadersMsg, GetBlockBodiesMsg, GetCodeMsg, GetReceiptsMsg, GetProofsV1Msg, SendTxMsg, SendTxV2Msg, GetTxStatusMsg, GetHeaderProofsMsg, GetProofsV2Msg, GetHelperTrieProofsMsg}
+	reqListV1 = []uint64{GetBlockHeadersMsg, GetBlockBodiesMsg, GetCodeMsg, GetReceiptsMsg, GetProofsV1Msg, SendTxMsg, GetHeaderProofsMsg}
+	reqListV2 = []uint64{GetBlockHeadersMsg, GetBlockBodiesMsg, GetCodeMsg, GetReceiptsMsg, SendTxV2Msg, GetTxStatusMsg, GetProofsV2Msg, GetHelperTrieProofsMsg}
+)
 
 // handleMsg is invoked whenever an inbound message is received from a remote
 // peer. The remote connection is torn down upon returning any error.
diff --git a/les/handler_test.go b/les/handler_test.go
index 43be7f41b1..a768482798 100644
--- a/les/handler_test.go
+++ b/les/handler_test.go
@@ -508,8 +508,9 @@ func TestTransactionStatusLes2(t *testing.T) {
 	test := func(tx *types.Transaction, send bool, expStatus txStatus) {
 		reqID++
 		if send {
-			cost := peer.GetRequestCost(SendTxV2Msg, 1)
-			sendRequest(peer.app, SendTxV2Msg, reqID, cost, types.Transactions{tx})
+			enc, _ := rlp.EncodeToBytes(types.Transactions{tx})
+			cost := peer.GetTxRelayCost(1, len(enc))
+			sendRequest(peer.app, SendTxV2Msg, reqID, cost, rlp.RawValue(enc))
 		} else {
 			cost := peer.GetRequestCost(GetTxStatusMsg, 1)
 			sendRequest(peer.app, GetTxStatusMsg, reqID, cost, []common.Hash{tx.Hash()})
diff --git a/les/peer.go b/les/peer.go
index 678384f0eb..5072010c53 100644
--- a/les/peer.go
+++ b/les/peer.go
@@ -42,6 +42,11 @@ var (
 
 const maxResponseErrors = 50 // number of invalid responses tolerated (makes the protocol less brittle but still avoids spam)
 
+// if the total encoded size of a sent transaction batch is over txSizeCostLimit
+// per transaction then the request cost is calculated as proportional to the
+// encoded size instead of the transaction count
+const txSizeCostLimit = 0x4000
+
 const (
 	announceTypeNone = iota
 	announceTypeSimple
@@ -163,7 +168,41 @@ func (p *peer) GetRequestCost(msgcode uint64, amount int) uint64 {
 	p.lock.RLock()
 	defer p.lock.RUnlock()
 
-	cost := p.fcCosts[msgcode].baseCost + p.fcCosts[msgcode].reqCost*uint64(amount)
+	costs := p.fcCosts[msgcode]
+	if costs == nil {
+		return 0
+	}
+	cost := costs.baseCost + costs.reqCost*uint64(amount)
+	if cost > p.fcServerParams.BufLimit {
+		cost = p.fcServerParams.BufLimit
+	}
+	return cost
+}
+
+func (p *peer) GetTxRelayCost(amount, size int) uint64 {
+	p.lock.RLock()
+	defer p.lock.RUnlock()
+
+	var msgcode uint64
+	switch p.version {
+	case lpv1:
+		msgcode = SendTxMsg
+	case lpv2:
+		msgcode = SendTxV2Msg
+	default:
+		panic(nil)
+	}
+
+	costs := p.fcCosts[msgcode]
+	if costs == nil {
+		return 0
+	}
+	cost := costs.baseCost + costs.reqCost*uint64(amount)
+	sizeCost := costs.baseCost + costs.reqCost*uint64(size)/txSizeCostLimit
+	if sizeCost > cost {
+		cost = sizeCost
+	}
+
 	if cost > p.fcServerParams.BufLimit {
 		cost = p.fcServerParams.BufLimit
 	}
@@ -307,9 +346,9 @@ func (p *peer) RequestTxStatus(reqID, cost uint64, txHashes []common.Hash) error
 	return sendRequest(p.rw, GetTxStatusMsg, reqID, cost, txHashes)
 }
 
-// SendTxStatus sends a batch of transactions to be added to the remote transaction pool.
-func (p *peer) SendTxs(reqID, cost uint64, txs types.Transactions) error {
-	p.Log().Debug("Fetching batch of transactions", "count", len(txs))
+// SendTxs sends a batch of transactions to be added to the remote transaction pool.
+func (p *peer) SendTxs(reqID, cost uint64, txs rlp.RawValue) error {
+	p.Log().Debug("Fetching batch of transactions", "size", len(txs))
 	switch p.version {
 	case lpv1:
 		return p2p.Send(p.rw, SendTxMsg, txs) // old message format does not include reqID
@@ -485,6 +524,20 @@ func (p *peer) Handshake(td *big.Int, head common.Hash, headNum uint64, genesis
 		p.fcServerParams = params
 		p.fcServer = flowcontrol.NewServerNode(params)
 		p.fcCosts = MRC.decode()
+		var checkList []uint64
+		switch p.version {
+		case lpv1:
+			checkList = reqListV1
+		case lpv2:
+			checkList = reqListV2
+		default:
+			panic(nil)
+		}
+		for _, msgCode := range checkList {
+			if p.fcCosts[msgCode] == nil {
+				return errResp(ErrUselessPeer, "peer does not support message %d", msgCode)
+			}
+		}
 	}
 
 	p.headInfo = &announceData{Td: rTd, Hash: rHash, Number: rNum}
diff --git a/les/txrelay.go b/les/txrelay.go
index 7a02cc837e..5decd6e93a 100644
--- a/les/txrelay.go
+++ b/les/txrelay.go
@@ -21,6 +21,7 @@ import (
 
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/rlp"
 )
 
 type ltrInfo struct {
@@ -113,21 +114,22 @@ func (self *LesTxRelay) send(txs types.Transactions, count int) {
 	for p, list := range sendTo {
 		pp := p
 		ll := list
+		enc, _ := rlp.EncodeToBytes(ll)
 
 		reqID := genReqID()
 		rq := &distReq{
 			getCost: func(dp distPeer) uint64 {
 				peer := dp.(*peer)
-				return peer.GetRequestCost(SendTxMsg, len(ll))
+				return peer.GetTxRelayCost(len(ll), len(enc))
 			},
 			canSend: func(dp distPeer) bool {
 				return dp.(*peer) == pp
 			},
 			request: func(dp distPeer) func() {
 				peer := dp.(*peer)
-				cost := peer.GetRequestCost(SendTxMsg, len(ll))
+				cost := peer.GetTxRelayCost(len(ll), len(enc))
 				peer.fcServer.QueueRequest(reqID, cost)
-				return func() { peer.SendTxs(reqID, cost, ll) }
+				return func() { peer.SendTxs(reqID, cost, enc) }
 			},
 		}
 		self.reqDist.queue(rq)
diff --git a/params/version.go b/params/version.go
index 5abe2ab95a..daff23bf4b 100644
--- a/params/version.go
+++ b/params/version.go
@@ -23,7 +23,7 @@ import (
 const (
 	VersionMajor = 1        // Major version component of the current release
 	VersionMinor = 8        // Minor version component of the current release
-	VersionPatch = 25       // Patch version component of the current release
+	VersionPatch = 26       // Patch version component of the current release
 	VersionMeta  = "stable" // Version metadata to append to the version string
 )
 
diff --git a/swarm/version/version.go b/swarm/version/version.go
index 6c393e9c7f..6b536bded9 100644
--- a/swarm/version/version.go
+++ b/swarm/version/version.go
@@ -23,7 +23,7 @@ import (
 const (
 	VersionMajor = 0        // Major version component of the current release
 	VersionMinor = 3        // Minor version component of the current release
-	VersionPatch = 13       // Patch version component of the current release
+	VersionPatch = 14       // Patch version component of the current release
 	VersionMeta  = "stable" // Version metadata to append to the version string
 )