diff --git a/les/costtracker.go b/les/costtracker.go
index 014b888c01b1c6e5d6e5ee5f56882e4b383bc027..332d73343123d2f65b19cedc58a3321a2983d486 100644
--- a/les/costtracker.go
+++ b/les/costtracker.go
@@ -346,12 +346,14 @@ func (table requestCostTable) getCost(code, amount uint64) uint64 {
 }
 
 // decode converts a cost list to a cost table
-func (list RequestCostList) decode() requestCostTable {
+func (list RequestCostList) decode(protocolLength uint64) requestCostTable {
 	table := make(requestCostTable)
 	for _, e := range list {
-		table[e.MsgCode] = &requestCosts{
-			baseCost: e.BaseCost,
-			reqCost:  e.ReqCost,
+		if e.MsgCode < protocolLength {
+			table[e.MsgCode] = &requestCosts{
+				baseCost: e.BaseCost,
+				reqCost:  e.ReqCost,
+			}
 		}
 	}
 	return table
diff --git a/les/peer.go b/les/peer.go
index a8aad3cd0b5c55b85f8ff9fd3d11232e5bb1e515..7a163cd1d0ef78164bf3776683685e95dbdb4619 100644
--- a/les/peer.go
+++ b/les/peer.go
@@ -479,7 +479,7 @@ func (p *peer) Handshake(td *big.Int, head common.Hash, headNum uint64, genesis
 			costList = testCostList()
 		}
 		send = send.add("flowControl/MRC", costList)
-		p.fcCosts = costList.decode()
+		p.fcCosts = costList.decode(ProtocolLengths[uint(p.version)])
 		p.fcParams = server.defParams
 	} else {
 		//on client node
@@ -571,7 +571,7 @@ func (p *peer) Handshake(td *big.Int, head common.Hash, headNum uint64, genesis
 		}
 		p.fcParams = params
 		p.fcServer = flowcontrol.NewServerNode(params, &mclock.System{})
-		p.fcCosts = MRC.decode()
+		p.fcCosts = MRC.decode(ProtocolLengths[uint(p.version)])
 		if !p.isOnlyAnnounce {
 			for msgCode := range reqAvgTimeCost {
 				if p.fcCosts[msgCode] == nil {
@@ -604,7 +604,10 @@ func (p *peer) updateFlowControl(update keyValueMap) {
 	}
 	var MRC RequestCostList
 	if update.get("flowControl/MRC", &MRC) == nil {
-		p.fcCosts = MRC.decode()
+		costUpdate := MRC.decode(ProtocolLengths[uint(p.version)])
+		for code, cost := range costUpdate {
+			p.fcCosts[code] = cost
+		}
 	}
 }
 
diff --git a/les/peer_test.go b/les/peer_test.go
index c5a7c238c209507d0e8663ca672b0ed22c9f8064..62adf90fe1f76e245833a1ca97f01c8c16da3657 100644
--- a/les/peer_test.go
+++ b/les/peer_test.go
@@ -13,7 +13,7 @@ import (
 
 const (
 	test_networkid   = 10
-	protocol_version = 2123
+	protocol_version = lpv2
 )
 
 var (