diff --git a/cmd/utils/flags.go b/cmd/utils/flags.go
index 179d351404..8356f52b28 100644
--- a/cmd/utils/flags.go
+++ b/cmd/utils/flags.go
@@ -1248,7 +1248,7 @@ func MakeChain(ctx *cli.Context, stack *node.Node) (chain *core.BlockChain, chai
 	}
 	var engine consensus.Engine
 	if config.XDPoS != nil {
-		engine = XDPoS.New(config.XDPoS, chainDb)
+		engine = XDPoS.New(config, chainDb)
 	} else {
 		engine = ethash.NewFaker()
 		if !ctx.GlobalBool(FakePoWFlag.Name) {
diff --git a/consensus/XDPoS/XDPoS.go b/consensus/XDPoS/XDPoS.go
index 869d0199d6..b6ff00490c 100644
--- a/consensus/XDPoS/XDPoS.go
+++ b/consensus/XDPoS/XDPoS.go
@@ -78,8 +78,9 @@ func (x *XDPoS) SubscribeForensicsEvent(ch chan<- types.ForensicsEvent) event.Su
 
 // New creates a XDPoS delegated-proof-of-stake consensus engine with the initial
 // signers set to the ones provided by the user.
-func New(config *params.XDPoSConfig, db ethdb.Database) *XDPoS {
+func New(chainConfig *params.ChainConfig, db ethdb.Database) *XDPoS {
 	log.Info("[New] initialise consensus engines")
+	config := chainConfig.XDPoS
 	// Set any missing consensus parameters to their defaults
 	if config.Epoch == 0 {
 		config.Epoch = utils.EpochLength
@@ -108,8 +109,8 @@ func New(config *params.XDPoSConfig, db ethdb.Database) *XDPoS {
 		WaitPeriodCh: waitPeriodCh,
 
 		signingTxsCache: signingTxsCache,
-		EngineV1:        engine_v1.New(config, db),
-		EngineV2:        engine_v2.New(config, db, waitPeriodCh),
+		EngineV1:        engine_v1.New(chainConfig, db),
+		EngineV2:        engine_v2.New(chainConfig, db, waitPeriodCh),
 	}
 }
 
@@ -138,8 +139,8 @@ func NewFaker(db ethdb.Database, chainConfig *params.ChainConfig) *XDPoS {
 		GetLendingService: func() utils.LendingService { return nil },
 
 		signingTxsCache: signingTxsCache,
-		EngineV1:        engine_v1.NewFaker(db, conf),
-		EngineV2:        engine_v2.New(conf, db, waitPeriodCh),
+		EngineV1:        engine_v1.NewFaker(db, chainConfig),
+		EngineV2:        engine_v2.New(chainConfig, db, waitPeriodCh),
 	}
 	return fakeEngine
 }
diff --git a/consensus/XDPoS/XDPoS_test.go b/consensus/XDPoS/XDPoS_test.go
index 0d36c8a05b..c4c555d494 100644
--- a/consensus/XDPoS/XDPoS_test.go
+++ b/consensus/XDPoS/XDPoS_test.go
@@ -10,7 +10,7 @@ import (
 
 func TestAdaptorShouldShareDbWithV1Engine(t *testing.T) {
 	database := rawdb.NewMemoryDatabase()
-	config := params.TestXDPoSMockChainConfig.XDPoS
+	config := params.TestXDPoSMockChainConfig
 	engine := New(config, database)
 
 	assert := assert.New(t)
diff --git a/consensus/XDPoS/engines/engine_v1/engine.go b/consensus/XDPoS/engines/engine_v1/engine.go
index c6e9c0053c..98b38607f0 100644
--- a/consensus/XDPoS/engines/engine_v1/engine.go
+++ b/consensus/XDPoS/engines/engine_v1/engine.go
@@ -38,6 +38,8 @@ const (
 // XDPoS is the delegated-proof-of-stake consensus engine proposed to support the
 // Ethereum testnet following the Ropsten attacks.
 type XDPoS_v1 struct {
+	chainConfig *params.ChainConfig // Chain & network configuration
+
 	config *params.XDPoSConfig // Consensus engine configuration parameters
 	db     ethdb.Database      // Database to store and retrieve snapshot checkpoints
 
@@ -79,7 +81,8 @@ func (x *XDPoS_v1) SigHash(header *types.Header) (hash common.Hash) {
 
 // New creates a XDPoS delegated-proof-of-stake consensus engine with the initial
 // signers set to the ones provided by the user.
-func New(config *params.XDPoSConfig, db ethdb.Database) *XDPoS_v1 {
+func New(chainConfig *params.ChainConfig, db ethdb.Database) *XDPoS_v1 {
+	config := chainConfig.XDPoS
 	// Set any missing consensus parameters to their defaults
 	conf := *config
 	if conf.Epoch == 0 {
@@ -91,6 +94,8 @@ func New(config *params.XDPoSConfig, db ethdb.Database) *XDPoS_v1 {
 	validatorSignatures, _ := lru.NewARC(utils.InmemorySnapshots)
 	verifiedHeaders, _ := lru.NewARC(utils.InmemorySnapshots)
 	return &XDPoS_v1{
+		chainConfig: chainConfig,
+
 		config: &conf,
 		db:     db,
 
@@ -778,7 +783,20 @@ func (x *XDPoS_v1) Prepare(chain consensus.ChainReader, header *types.Header) er
 	return nil
 }
 
+// Update masternodes into snapshot. In V1, truncating ms[:MaxMasternodes] is done in this function.
 func (x *XDPoS_v1) UpdateMasternodes(chain consensus.ChainReader, header *types.Header, ms []utils.Masternode) error {
+	var maxMasternodes int
+	// check if block number is increase ms checkpoint
+	if x.chainConfig.IsTIPIncreaseMasternodes(header.Number) || (x.config.V2.SwitchBlock != nil && header.Number.Cmp(x.config.V2.SwitchBlock) == 1) {
+		// using new masterndoes
+		maxMasternodes = common.MaxMasternodesV2
+	} else {
+		// using old masterndoes
+		maxMasternodes = common.MaxMasternodes
+	}
+	if len(ms) > maxMasternodes {
+		ms = ms[:maxMasternodes]
+	}
 	number := header.Number.Uint64()
 	log.Trace("take snapshot", "number", number, "hash", header.Hash())
 	// get snapshot
@@ -1007,10 +1025,10 @@ func (x *XDPoS_v1) getSignersFromContract(chain consensus.ChainReader, checkpoin
 	return signers, nil
 }
 
-func NewFaker(db ethdb.Database, config *params.XDPoSConfig) *XDPoS_v1 {
+func NewFaker(db ethdb.Database, chainConfig *params.ChainConfig) *XDPoS_v1 {
 	var fakeEngine *XDPoS_v1
 	// Set any missing consensus parameters to their defaults
-	conf := config
+	conf := chainConfig.XDPoS
 
 	// Allocate the snapshot caches and create the engine
 	recents, _ := lru.NewARC(utils.InmemorySnapshots)
@@ -1018,6 +1036,8 @@ func NewFaker(db ethdb.Database, config *params.XDPoSConfig) *XDPoS_v1 {
 	validatorSignatures, _ := lru.NewARC(utils.InmemorySnapshots)
 	verifiedHeaders, _ := lru.NewARC(utils.InmemorySnapshots)
 	fakeEngine = &XDPoS_v1{
+		chainConfig: chainConfig,
+
 		config:              conf,
 		db:                  db,
 		recents:             recents,
diff --git a/consensus/XDPoS/engines/engine_v2/engine.go b/consensus/XDPoS/engines/engine_v2/engine.go
index c71e41c72f..0ff6aa9c18 100644
--- a/consensus/XDPoS/engines/engine_v2/engine.go
+++ b/consensus/XDPoS/engines/engine_v2/engine.go
@@ -24,6 +24,8 @@ import (
 )
 
 type XDPoS_v2 struct {
+	chainConfig *params.ChainConfig // Chain & network configuration
+
 	config       *params.XDPoSConfig // Consensus engine configuration parameters
 	db           ethdb.Database      // Database to store and retrieve snapshot checkpoints
 	isInitilised bool                // status of v2 variables
@@ -64,7 +66,8 @@ type XDPoS_v2 struct {
 	votePoolCollectionTime time.Time
 }
 
-func New(config *params.XDPoSConfig, db ethdb.Database, waitPeriodCh chan int) *XDPoS_v2 {
+func New(chainConfig *params.ChainConfig, db ethdb.Database, waitPeriodCh chan int) *XDPoS_v2 {
+	config := chainConfig.XDPoS
 	// Setup timeoutTimer
 	duration := time.Duration(config.V2.CurrentConfig.TimeoutPeriod) * time.Second
 	timeoutTimer := countdown.NewCountDown(duration)
@@ -77,6 +80,8 @@ func New(config *params.XDPoSConfig, db ethdb.Database, waitPeriodCh chan int) *
 	timeoutPool := utils.NewPool()
 	votePool := utils.NewPool()
 	engine := &XDPoS_v2{
+		chainConfig: chainConfig,
+
 		config:       config,
 		db:           db,
 		isInitilised: false,
@@ -988,7 +993,11 @@ func (x *XDPoS_v2) GetPenalties(chain consensus.ChainReader, header *types.Heade
 	return epochSwitchInfo.Penalties
 }
 
+// Calculate masternodes for a block number and parent hash. In V2, truncating candidates[:MaxMasternodes] is done in this function.
 func (x *XDPoS_v2) calcMasternodes(chain consensus.ChainReader, blockNum *big.Int, parentHash common.Hash) ([]common.Address, []common.Address, error) {
+	// using new max masterndoes
+	maxMasternodes := common.MaxMasternodesV2
+
 	snap, err := x.getSnapshot(chain, blockNum.Uint64(), false)
 	if err != nil {
 		log.Error("[calcMasternodes] Adaptor v2 getSnapshot has error", "err", err)
@@ -998,11 +1007,17 @@ func (x *XDPoS_v2) calcMasternodes(chain consensus.ChainReader, blockNum *big.In
 
 	if blockNum.Uint64() == x.config.V2.SwitchBlock.Uint64()+1 {
 		log.Info("[calcMasternodes] examing first v2 block")
+		if len(candidates) > maxMasternodes {
+			candidates = candidates[:maxMasternodes]
+		}
 		return candidates, []common.Address{}, nil
 	}
 
 	if x.HookPenalty == nil {
 		log.Info("[calcMasternodes] no hook penalty defined")
+		if len(candidates) > maxMasternodes {
+			candidates = candidates[:maxMasternodes]
+		}
 		return candidates, []common.Address{}, nil
 	}
 
@@ -1012,6 +1027,18 @@ func (x *XDPoS_v2) calcMasternodes(chain consensus.ChainReader, blockNum *big.In
 		return nil, nil, err
 	}
 	masternodes := common.RemoveItemFromArray(candidates, penalties)
+	if len(masternodes) > maxMasternodes {
+		masternodes = masternodes[:maxMasternodes]
+	}
+	if len(masternodes) < x.config.V2.CurrentConfig.CertThreshold {
+		log.Warn("[calcMasternodes] Current epoch masternodes less than threshold", "number", blockNum, "masternodes", len(masternodes), "threshold", x.config.V2.CurrentConfig.CertThreshold)
+		for i, a := range masternodes {
+			log.Warn("final masternode", "i", i, "addr", a)
+		}
+		for i, a := range penalties {
+			log.Warn("penalty", "i", i, "addr", a)
+		}
+	}
 	return masternodes, penalties, nil
 
 }
diff --git a/consensus/tests/engine_v1_tests/block_signer_test.go b/consensus/tests/engine_v1_tests/block_signer_test.go
index df176d8114..673c23b1bc 100644
--- a/consensus/tests/engine_v1_tests/block_signer_test.go
+++ b/consensus/tests/engine_v1_tests/block_signer_test.go
@@ -154,6 +154,7 @@ func TestUpdateSignerListIfVotedBeforeGap(t *testing.T) {
 	if err != nil {
 		t.Fatalf("Failed while trying to get signers")
 	}
+	assert.Equal(t, common.MaxMasternodes, len(signers))
 	// Now, we voted acc 1 to be in the signerList, which will kick out acc3 because it has less funds
 	if signers[acc3Addr.Hex()] == true {
 		debugMessage(backend, signers, t)
@@ -195,6 +196,7 @@ func TestCallUpdateM1WithSmartContractTranscation(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
+	assert.Equal(t, common.MaxMasternodes, len(signers))
 	if signers[acc1Addr.Hex()] != true {
 		debugMessage(backend, signers, t)
 		t.Fatalf("account 1 should sit in the signer list")
@@ -244,6 +246,7 @@ func TestCallUpdateM1WhenForkedBlockBackToMainChain(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
+	assert.Equal(t, common.MaxMasternodes, len(signers))
 	if signers[acc1Addr.Hex()] != true {
 		debugMessage(backend, signers, t)
 		t.Fatalf("account 1 should sit in the signer list")
@@ -279,6 +282,7 @@ func TestCallUpdateM1WhenForkedBlockBackToMainChain(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
+	assert.Equal(t, common.MaxMasternodes, len(signers))
 	// Should not run the `updateM1` for forked chain, hence account3 still exit
 	if signers[acc3Addr.Hex()] != true {
 		debugMessage(backend, signers, t)
@@ -312,6 +316,7 @@ func TestCallUpdateM1WhenForkedBlockBackToMainChain(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
+	assert.Equal(t, common.MaxMasternodes, len(signers))
 	if signers[acc2Addr.Hex()] != true {
 		debugMessage(backend, signers, t)
 		t.Fatalf("account 2 should sit in the signer list")
@@ -325,6 +330,7 @@ func TestCallUpdateM1WhenForkedBlockBackToMainChain(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
+	assert.Equal(t, common.MaxMasternodes, len(signers))
 	if signers[acc2Addr.Hex()] != true {
 		debugMessage(backend, signers, t)
 		t.Fatalf("account 2 should sit in the signer list")
@@ -338,6 +344,7 @@ func TestCallUpdateM1WhenForkedBlockBackToMainChain(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
+	assert.Equal(t, common.MaxMasternodes, len(signers))
 	if signers[acc2Addr.Hex()] != true {
 		debugMessage(backend, signers, t)
 		t.Fatalf("acc2Addr should sit in the signer list")
@@ -404,6 +411,7 @@ func TestStatesShouldBeUpdatedWhenForkedBlockBecameMainChainAtGapBlock(t *testin
 	if err != nil {
 		t.Fatal(err)
 	}
+	assert.Equal(t, common.MaxMasternodes, len(signers))
 	if signers[acc1Addr.Hex()] != true {
 		debugMessage(backend, signers, t)
 		t.Fatalf("account 1 should sit in the signer list")
@@ -445,6 +453,7 @@ func TestStatesShouldBeUpdatedWhenForkedBlockBecameMainChainAtGapBlock(t *testin
 	if err != nil {
 		t.Fatal(err)
 	}
+	assert.Equal(t, common.MaxMasternodes, len(signers))
 	// Should not run the `updateM1` for forked chain, hence account3 still exit
 	if signers[acc3Addr.Hex()] != true {
 		debugMessage(backend, signers, t)
@@ -473,6 +482,7 @@ func TestStatesShouldBeUpdatedWhenForkedBlockBecameMainChainAtGapBlock(t *testin
 	if err != nil {
 		t.Fatal(err)
 	}
+	assert.Equal(t, common.MaxMasternodes, len(signers))
 	if signers[acc2Addr.Hex()] != true {
 		debugMessage(backend, signers, t)
 		t.Fatalf("account 2 should sit in the signer list")
@@ -482,6 +492,7 @@ func TestStatesShouldBeUpdatedWhenForkedBlockBecameMainChainAtGapBlock(t *testin
 	if err != nil {
 		t.Fatal(err)
 	}
+	assert.Equal(t, common.MaxMasternodes, len(signers))
 	if signers[acc2Addr.Hex()] != true {
 		debugMessage(backend, signers, t)
 		t.Fatalf("account 2 should sit in the signer list")
@@ -491,6 +502,7 @@ func TestStatesShouldBeUpdatedWhenForkedBlockBecameMainChainAtGapBlock(t *testin
 	if err != nil {
 		t.Fatal(err)
 	}
+	assert.Equal(t, common.MaxMasternodes, len(signers))
 	if signers[acc2Addr.Hex()] != true {
 		debugMessage(backend, signers, t)
 		t.Fatalf("acc2Addr should sit in the signer list")
@@ -564,6 +576,7 @@ func TestVoteShouldNotBeAffectedByFork(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
+	assert.Equal(t, common.MaxMasternodes, len(signers))
 	if signers[acc1Addr.Hex()] == true {
 		debugMessage(backend, signers, t)
 		t.Fatalf("account 1 should NOT sit in the signer list")
@@ -623,6 +636,7 @@ func TestVoteShouldNotBeAffectedByFork(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
+	assert.Equal(t, common.MaxMasternodes, len(signers))
 
 	// Should run the `updateM1` for forked chain, but it should not be affected by the voted block 451A which is not on the mainchain anymore
 	if signers[acc3Addr.Hex()] != true {
@@ -630,63 +644,3 @@ func TestVoteShouldNotBeAffectedByFork(t *testing.T) {
 		t.Fatalf("account 3 should sit in the signer list as previos block result")
 	}
 }
-
-/*
-  V2 Consensus
-*/
-/*
-// Pending for creating cross version blocks
-func TestV2UpdateSignerListIfVotedBeforeGap(t *testing.T) {
-	config := params.TestXDPoSMockChainConfig
-	blockchain, backend, parentBlock, signer, signFn := PrepareXDCTestBlockChain(t, int(config.XDPoS.Epoch)+GAP-2, config)
-	// Insert first Block 1349
-	t.Logf("Inserting block with propose at 1349...")
-	blockCoinbaseA := "0xaaa0000000000000000000000000000000001349"
-	tx, err := voteTX(37117, 0, acc1Addr.String())
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	//Get from block validator error message
-	merkleRoot := "46234e9cd7e85a267f7f0435b15256a794a2f6d65cc98cdbd21dcd10a01d9772"
-	header := &types.Header{
-		Root:       common.HexToHash(merkleRoot),
-		Number:     big.NewInt(int64(1349)),
-		ParentHash: parentBlock.Hash(),
-		Coinbase:   common.HexToAddress(blockCoinbaseA),
-	}
-	block1349, err := insertBlockTxs(blockchain, header, []*types.Transaction{tx}, signer, signFn, blockchain.Config())
-	if err != nil {
-		t.Fatal(err)
-	}
-	parentBlock = block1349
-
-	// Now, let's mine another block to trigger the GAP block signerList update
-	block1350CoinbaseAddress := "0xaaa0000000000000000000000000000000001350"
-	merkleRoot = "46234e9cd7e85a267f7f0435b15256a794a2f6d65cc98cdbd21dcd10a01d9772"
-	header = &types.Header{
-		Root:       common.HexToHash(merkleRoot),
-		Number:     big.NewInt(int64(1350)),
-		ParentHash: parentBlock.Hash(),
-		Coinbase:   common.HexToAddress(block1350CoinbaseAddress),
-	}
-	block1350, err := insertBlock(blockchain, header)
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	signers, err := GetSnapshotSigner(blockchain, block1350.Header())
-	if err != nil {
-		t.Fatalf("Failed while trying to get signers")
-	}
-	// Now, we voted acc 1 to be in the signerList, which will kick out acc3 because it has less funds
-	if signers[acc3Addr.Hex()] == true {
-		debugMessage(backend, signers, t)
-		t.Fatalf("account 3 should NOT sit in the signer list")
-	}
-	if signers[acc1Addr.Hex()] != true {
-		debugMessage(backend, signers, t)
-		t.Fatalf("account 1 should sit in the signer list")
-	}
-}
-*/
diff --git a/consensus/tests/engine_v2_tests/adaptor_test.go b/consensus/tests/engine_v2_tests/adaptor_test.go
index 6eb2ff65e1..564a16f585 100644
--- a/consensus/tests/engine_v2_tests/adaptor_test.go
+++ b/consensus/tests/engine_v2_tests/adaptor_test.go
@@ -180,7 +180,7 @@ func TestAdaptorGetMasternodesV2(t *testing.T) {
 	adaptor := blockchain.Engine().(*XDPoS.XDPoS)
 	blockNum := 901
 	blockCoinBase := "0x111000000000000000000000000000000123"
-	currentBlock = CreateBlock(blockchain, params.TestXDPoSMockChainConfig, currentBlock, blockNum, 1, blockCoinBase, signer, signFn, nil, nil)
+	currentBlock = CreateBlock(blockchain, params.TestXDPoSMockChainConfig, currentBlock, blockNum, 1, blockCoinBase, signer, signFn, nil, nil, "")
 
 	// block 901 is the first v2 block, and is treated as epoch switch block
 	err := blockchain.InsertBlock(currentBlock)
@@ -190,7 +190,7 @@ func TestAdaptorGetMasternodesV2(t *testing.T) {
 	masternodes1ByNumber := adaptor.GetMasternodesByNumber(blockchain, currentBlock.NumberU64())
 	assert.True(t, reflect.DeepEqual(masternodes1, masternodes1ByNumber), "at block number", blockNum)
 	for blockNum = 902; blockNum < 915; blockNum++ {
-		currentBlock = CreateBlock(blockchain, params.TestXDPoSMockChainConfig, currentBlock, blockNum, int64(blockNum-900), blockCoinBase, signer, signFn, nil, nil)
+		currentBlock = CreateBlock(blockchain, params.TestXDPoSMockChainConfig, currentBlock, blockNum, int64(blockNum-900), blockCoinBase, signer, signFn, nil, nil, "")
 		err = blockchain.InsertBlock(currentBlock)
 		assert.Nil(t, err)
 		masternodes2 := adaptor.GetMasternodes(blockchain, currentBlock.Header())
@@ -213,7 +213,7 @@ func TestGetCurrentEpochSwitchBlock(t *testing.T) {
 	// V2
 	blockNum := 901
 	blockCoinBase := "0x111000000000000000000000000000000123"
-	currentBlock = CreateBlock(blockchain, params.TestXDPoSMockChainConfig, currentBlock, blockNum, 1, blockCoinBase, signer, signFn, nil, nil)
+	currentBlock = CreateBlock(blockchain, params.TestXDPoSMockChainConfig, currentBlock, blockNum, 1, blockCoinBase, signer, signFn, nil, nil, "")
 	err = blockchain.InsertBlock(currentBlock)
 	assert.Nil(t, err)
 	currentCheckpointNumber, epochNum, err = adaptor.GetCurrentEpochSwitchBlock(blockchain, currentBlock.Number())
@@ -222,7 +222,7 @@ func TestGetCurrentEpochSwitchBlock(t *testing.T) {
 	assert.Equal(t, uint64(1), epochNum)
 
 	for blockNum = 902; blockNum < 915; blockNum++ {
-		currentBlock = CreateBlock(blockchain, params.TestXDPoSMockChainConfig, currentBlock, blockNum, int64(blockNum-900), blockCoinBase, signer, signFn, nil, nil)
+		currentBlock = CreateBlock(blockchain, params.TestXDPoSMockChainConfig, currentBlock, blockNum, int64(blockNum-900), blockCoinBase, signer, signFn, nil, nil, "")
 
 		err = blockchain.InsertBlock(currentBlock)
 		assert.Nil(t, err)
@@ -248,13 +248,13 @@ func TestGetParentBlock(t *testing.T) {
 	// V2
 	blockNum := 901
 	blockCoinBase := "0x111000000000000000000000000000000123"
-	block901 := CreateBlock(blockchain, params.TestXDPoSMockChainConfig, block900, blockNum, 1, blockCoinBase, signer, signFn, nil, nil)
+	block901 := CreateBlock(blockchain, params.TestXDPoSMockChainConfig, block900, blockNum, 1, blockCoinBase, signer, signFn, nil, nil, "")
 	err = blockchain.InsertBlock(block901)
 	assert.Nil(t, err)
 
 	// let's inject another one, but the highestedQC has not been updated, so it shall still point to 900
 	blockNum = 902
-	block902 := CreateBlock(blockchain, params.TestXDPoSMockChainConfig, block901, blockNum, 1, blockCoinBase, signer, signFn, nil, nil)
+	block902 := CreateBlock(blockchain, params.TestXDPoSMockChainConfig, block901, blockNum, 1, blockCoinBase, signer, signFn, nil, nil, "")
 	err = blockchain.InsertBlock(block902)
 	assert.Nil(t, err)
 	block = adaptor.FindParentBlockToAssign(blockchain, block902)
diff --git a/consensus/tests/engine_v2_tests/authorised_masternode_test.go b/consensus/tests/engine_v2_tests/authorised_masternode_test.go
index d93a5747f1..adf0e38b97 100644
--- a/consensus/tests/engine_v2_tests/authorised_masternode_test.go
+++ b/consensus/tests/engine_v2_tests/authorised_masternode_test.go
@@ -17,7 +17,7 @@ func TestIsAuthorisedMNForConsensusV2(t *testing.T) {
 	adaptor := blockchain.Engine().(*XDPoS.XDPoS)
 	blockNum := 902
 	blockCoinBase := "0x111000000000000000000000000000000123"
-	currentBlock = CreateBlock(blockchain, params.TestXDPoSMockChainConfig, currentBlock, blockNum, 2, blockCoinBase, signer, signFn, nil, nil)
+	currentBlock = CreateBlock(blockchain, params.TestXDPoSMockChainConfig, currentBlock, blockNum, 2, blockCoinBase, signer, signFn, nil, nil, "")
 	err := blockchain.InsertBlock(currentBlock)
 	assert.Nil(t, err)
 	// As long as the address is in the master node list, they are all valid
@@ -38,7 +38,7 @@ func TestIsYourTurnConsensusV2(t *testing.T) {
 	adaptor := blockchain.Engine().(*XDPoS.XDPoS)
 	blockNum := 901
 	blockCoinBase := "0x111000000000000000000000000000000123"
-	currentBlock = CreateBlock(blockchain, params.TestXDPoSMockChainConfig, currentBlock, blockNum, 1, blockCoinBase, signer, signFn, nil, nil)
+	currentBlock = CreateBlock(blockchain, params.TestXDPoSMockChainConfig, currentBlock, blockNum, 1, blockCoinBase, signer, signFn, nil, nil, "")
 	currentBlockHeader := currentBlock.Header()
 	currentBlockHeader.Time = big.NewInt(time.Now().Unix())
 	err := blockchain.InsertBlock(currentBlock)
@@ -64,7 +64,7 @@ func TestIsYourTurnConsensusV2(t *testing.T) {
 
 	// We continue to grow the chain which will increase the round number
 	blockNum = 902
-	currentBlock = CreateBlock(blockchain, params.TestXDPoSMockChainConfig, currentBlock, blockNum, int64(blockNum-900), blockCoinBase, signer, signFn, nil, nil)
+	currentBlock = CreateBlock(blockchain, params.TestXDPoSMockChainConfig, currentBlock, blockNum, int64(blockNum-900), blockCoinBase, signer, signFn, nil, nil, "")
 	err = blockchain.InsertBlock(currentBlock)
 	assert.Nil(t, err)
 	time.Sleep(time.Duration(minePeriod) * time.Second)
@@ -89,7 +89,7 @@ func TestIsYourTurnConsensusV2CrossConfig(t *testing.T) {
 	adaptor := blockchain.Engine().(*XDPoS.XDPoS)
 	blockNum := 910 // 910 is new config switch block
 	blockCoinBase := "0x111000000000000000000000000000000123"
-	currentBlock = CreateBlock(blockchain, params.TestXDPoSMockChainConfig, currentBlock, blockNum, 10, blockCoinBase, signer, signFn, nil, nil)
+	currentBlock = CreateBlock(blockchain, params.TestXDPoSMockChainConfig, currentBlock, blockNum, 10, blockCoinBase, signer, signFn, nil, nil, "")
 	currentBlockHeader := currentBlock.Header()
 	currentBlockHeader.Time = big.NewInt(time.Now().Unix())
 	err := blockchain.InsertBlock(currentBlock)
diff --git a/consensus/tests/engine_v2_tests/helper.go b/consensus/tests/engine_v2_tests/helper.go
index 648de3a373..854eebd124 100644
--- a/consensus/tests/engine_v2_tests/helper.go
+++ b/consensus/tests/engine_v2_tests/helper.go
@@ -30,6 +30,7 @@ import (
 	"github.com/XinFinOrg/XDPoSChain/log"
 	"github.com/XinFinOrg/XDPoSChain/params"
 	"github.com/XinFinOrg/XDPoSChain/rlp"
+	"github.com/stretchr/testify/assert"
 )
 
 type masterNodes map[string]big.Int
@@ -199,6 +200,90 @@ func getCommonBackend(t *testing.T, chainConfig *params.ChainConfig) *backends.S
 	return contractBackend2
 }
 
+func getMultiCandidatesBackend(t *testing.T, chainConfig *params.ChainConfig, n int) *backends.SimulatedBackend {
+	assert.GreaterOrEqual(t, n, 4)
+	// initial helper backend, give a very large gas limit
+	contractBackendForSC := backends.NewXDCSimulatedBackend(core.GenesisAlloc{
+		voterAddr: {Balance: new(big.Int).SetUint64(10000000000)},
+	}, 1000000000, chainConfig)
+
+	transactOpts := bind.NewKeyedTransactor(voterKey)
+
+	var candidates []common.Address
+	var caps []*big.Int
+	defalutCap := new(big.Int)
+	defalutCap.SetString("1000000000", 10)
+
+	for i := 1; i <= n-4; i++ {
+		addr := fmt.Sprintf("%04d", i)
+		candidates = append(candidates, common.StringToAddress(addr))
+		caps = append(caps, defalutCap)
+	}
+
+	acc1Cap, acc2Cap, acc3Cap, voterCap := new(big.Int), new(big.Int), new(big.Int), new(big.Int)
+
+	acc1Cap.SetString("10000001", 10)
+	acc2Cap.SetString("10000002", 10)
+	acc3Cap.SetString("10000003", 10)
+	voterCap.SetString("2000000000", 10) // give voter the highest cap to make it win the masternode selection
+
+	caps = append(caps, voterCap, acc1Cap, acc2Cap, acc3Cap)
+	candidates = append(candidates, voterAddr, acc1Addr, acc2Addr, acc3Addr)
+
+	// create validator smart contract
+	validatorSCAddr, _, _, err := contractValidator.DeployXDCValidator(
+		transactOpts,
+		contractBackendForSC,
+		candidates,
+		caps,
+		voterAddr, // first owner, not used
+		big.NewInt(50000),
+		big.NewInt(1),
+		big.NewInt(99),
+		big.NewInt(100),
+		big.NewInt(100),
+	)
+	if err != nil {
+		t.Fatalf("can't deploy root registry: %v", err)
+	}
+
+	contractBackendForSC.Commit() // Write into database(state)
+
+	// Prepare Code and Storage
+	d := time.Now().Add(3000 * time.Millisecond)
+	ctx, cancel := context.WithDeadline(context.Background(), d)
+	defer cancel()
+
+	code, _ := contractBackendForSC.CodeAt(ctx, validatorSCAddr, nil)
+	storage := make(map[common.Hash]common.Hash)
+	f := func(key, val common.Hash) bool {
+		decode := []byte{}
+		trim := bytes.TrimLeft(val.Bytes(), "\x00")
+		err := rlp.DecodeBytes(trim, &decode)
+		if err != nil {
+			t.Fatalf("Failed while decode byte")
+		}
+		storage[key] = common.BytesToHash(decode)
+		log.Info("DecodeBytes", "value", val.String(), "decode", storage[key].String())
+		return true
+	}
+	err = contractBackendForSC.ForEachStorageAt(ctx, validatorSCAddr, nil, f)
+	if err != nil {
+		t.Fatalf("Failed while trying to read all keys from SC")
+	}
+
+	// create test backend with smart contract in it
+	contractBackend2 := backends.NewXDCSimulatedBackend(core.GenesisAlloc{
+		acc1Addr:  {Balance: new(big.Int).SetUint64(10000000000)},
+		acc2Addr:  {Balance: new(big.Int).SetUint64(10000000000)},
+		acc3Addr:  {Balance: new(big.Int).SetUint64(10000000000)},
+		voterAddr: {Balance: new(big.Int).SetUint64(10000000000)},
+		common.HexToAddress(common.MasternodeVotingSMC): {Balance: new(big.Int).SetUint64(1), Code: code, Storage: storage}, // Binding the MasternodeVotingSMC with newly created 'code' for SC execution
+	}, 10000000, chainConfig)
+
+	return contractBackend2
+}
+
 func signingTxWithKey(header *types.Header, nonce uint64, privateKey *ecdsa.PrivateKey) (*types.Transaction, error) {
 	tx := contracts.CreateTxSign(header.Number, header.Hash(), nonce, common.HexToAddress(common.BlockSigners))
 	s := types.NewEIP155Signer(big.NewInt(chainID))
@@ -316,7 +401,7 @@ func PrepareXDCTestBlockChainForV2Engine(t *testing.T, numOfBlocks int, chainCon
 			blockCoinBase = signer.Hex()
 		}
 		roundNumber := int64(i) - chainConfig.XDPoS.V2.SwitchBlock.Int64()
-		block := CreateBlock(blockchain, chainConfig, currentBlock, i, roundNumber, blockCoinBase, signer, signFn, nil, nil)
+		block := CreateBlock(blockchain, chainConfig, currentBlock, i, roundNumber, blockCoinBase, signer, signFn, nil, nil, "")
 
 		err = blockchain.InsertBlock(block)
 		if err != nil {
@@ -338,7 +423,7 @@ func PrepareXDCTestBlockChainForV2Engine(t *testing.T, numOfBlocks int, chainCon
 				forkedBlockRoundNumber = roundNumber + int64(*forkedBlockOptions.numOfForkedBlocks)
 			}
 
-			forkedBlock := CreateBlock(blockchain, chainConfig, currentForkBlock, i, forkedBlockRoundNumber, forkedBlockCoinBase, signer, signFn, nil, forkedBlockOptions.signersKey)
+			forkedBlock := CreateBlock(blockchain, chainConfig, currentForkBlock, i, forkedBlockRoundNumber, forkedBlockCoinBase, signer, signFn, nil, forkedBlockOptions.signersKey, "")
 
 			err = blockchain.InsertBlock(forkedBlock)
 			if err != nil {
@@ -403,7 +488,7 @@ func PrepareXDCTestBlockChainWithPenaltyForV2Engine(t *testing.T, numOfBlocks in
 		}
 		roundNumber := int64(i) - chainConfig.XDPoS.V2.SwitchBlock.Int64()
 		// use signer itself as penalty
-		block := CreateBlock(blockchain, chainConfig, currentBlock, i, roundNumber, blockCoinBase, signer, signFn, signer[:], nil)
+		block := CreateBlock(blockchain, chainConfig, currentBlock, i, roundNumber, blockCoinBase, signer, signFn, signer[:], nil, "")
 
 		err = blockchain.InsertBlock(block)
 		if err != nil {
@@ -421,9 +506,62 @@ func PrepareXDCTestBlockChainWithPenaltyForV2Engine(t *testing.T, numOfBlocks in
 	return blockchain, backend, currentBlock, signer, signFn
 }
 
-func CreateBlock(blockchain *BlockChain, chainConfig *params.ChainConfig, startingBlock *types.Block, blockNumber int, roundNumber int64, blockCoinBase string, signer common.Address, signFn func(account accounts.Account, hash []byte) ([]byte, error), penalties []byte, signersKey []*ecdsa.PrivateKey) *types.Block {
+// V2 concensus engine, compared to PrepareXDCTestBlockChainForV2Engine: (1) no forking (2) 128 masternode candidates
+func PrepareXDCTestBlockChainWith128Candidates(t *testing.T, numOfBlocks int, chainConfig *params.ChainConfig) (*BlockChain, *backends.SimulatedBackend, *types.Block, common.Address, func(account accounts.Account, hash []byte) ([]byte, error)) {
+	// Preparation
+	var err error
+	signer, signFn, err := backends.SimulateWalletAddressAndSignFn()
+	if err != nil {
+		t.Fatal("Error while creating simulated wallet for generating singer address and signer fn: ", err)
+	}
+	backend := getMultiCandidatesBackend(t, chainConfig, 128)
+	blockchain := backend.GetBlockChain()
+	blockchain.Client = backend
+
+	engine := blockchain.Engine().(*XDPoS.XDPoS)
+
+	// Authorise
+	engine.Authorize(signer, signFn)
+
+	currentBlock := blockchain.Genesis()
+
+	go func() {
+		for range core.CheckpointCh {
+			checkpointChanMsg := <-core.CheckpointCh
+			log.Info("[V2] Got a message from core CheckpointChan!", "msg", checkpointChanMsg)
+		}
+	}()
+
+	// Insert initial blocks
+	for i := 1; i <= numOfBlocks; i++ {
+		blockCoinBase := fmt.Sprintf("0x111000000000000000000000000000000%03d", i)
+		// for v2 blocks, fill in correct coinbase
+		if int64(i) > chainConfig.XDPoS.V2.SwitchBlock.Int64() {
+			blockCoinBase = signer.Hex()
+		}
+		roundNumber := int64(i) - chainConfig.XDPoS.V2.SwitchBlock.Int64()
+		block := CreateBlock(blockchain, chainConfig, currentBlock, i, roundNumber, blockCoinBase, signer, signFn, nil, nil, "b345a8560bd51926803dd17677c9f0751193914a851a4ec13063d6bf50220b53")
+		err = blockchain.InsertBlock(block)
+		if err != nil {
+			t.Fatal(err)
+		}
+		currentBlock = block
+	}
+
+	// Update Signer as there is no previous signer assigned
+	err = UpdateSigner(blockchain)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	return blockchain, backend, currentBlock, signer, signFn
+}
+
+func CreateBlock(blockchain *BlockChain, chainConfig *params.ChainConfig, startingBlock *types.Block, blockNumber int, roundNumber int64, blockCoinBase string, signer common.Address, signFn func(account accounts.Account, hash []byte) ([]byte, error), penalties []byte, signersKey []*ecdsa.PrivateKey, merkleRoot string) *types.Block {
 	currentBlock := startingBlock
-	merkleRoot := "35999dded35e8db12de7e6c1471eb9670c162eec616ecebbaf4fddd4676fb930"
+	if len(merkleRoot) == 0 {
+		merkleRoot = "35999dded35e8db12de7e6c1471eb9670c162eec616ecebbaf4fddd4676fb930"
+	}
 	var header *types.Header
 
 	if big.NewInt(int64(blockNumber)).Cmp(chainConfig.XDPoS.V2.SwitchBlock) == 1 { // Build engine v2 compatible extra data field
diff --git a/consensus/tests/engine_v2_tests/initial_test.go b/consensus/tests/engine_v2_tests/initial_test.go
index 09446171d4..438fdf8b76 100644
--- a/consensus/tests/engine_v2_tests/initial_test.go
+++ b/consensus/tests/engine_v2_tests/initial_test.go
@@ -59,7 +59,7 @@ func TestInitialOtherV2Block(t *testing.T) {
 
 	blockCoinBase := "0x111000000000000000000000000000000123"
 	for blockNum := 901; blockNum <= 910; blockNum++ {
-		currentBlock = CreateBlock(blockchain, params.TestXDPoSMockChainConfig, currentBlock, blockNum, int64(blockNum-900), blockCoinBase, signer, signFn, nil, nil)
+		currentBlock = CreateBlock(blockchain, params.TestXDPoSMockChainConfig, currentBlock, blockNum, int64(blockNum-900), blockCoinBase, signer, signFn, nil, nil, "")
 		err := blockchain.InsertBlock(currentBlock)
 		assert.Nil(t, err)
 	}
diff --git a/consensus/tests/engine_v2_tests/mine_test.go b/consensus/tests/engine_v2_tests/mine_test.go
index a56658e1e8..4ed5bd2c96 100644
--- a/consensus/tests/engine_v2_tests/mine_test.go
+++ b/consensus/tests/engine_v2_tests/mine_test.go
@@ -222,3 +222,63 @@ func TestPrepareHappyPath(t *testing.T) {
 	assert.Equal(t, types.Round(4), decodedExtraField.Round)
 	assert.Equal(t, types.Round(0), decodedExtraField.QuorumCert.ProposedBlockInfo.Round)
 }
+
+// test if we have 128 candidates, then snapshot will store all of them, and when preparing (and verifying) candidates is truncated to MaxMasternodes
+func TestUpdateMultipleMasterNodes(t *testing.T) {
+	config := params.TestXDPoSMockChainConfig
+	blockchain, _, currentBlock, signer, signFn := PrepareXDCTestBlockChainWith128Candidates(t, int(config.XDPoS.Epoch+config.XDPoS.Gap)-1, config)
+	adaptor := blockchain.Engine().(*XDPoS.XDPoS)
+	x := adaptor.EngineV2
+	// Insert block 1350
+	t.Logf("Inserting block with propose at 1350...")
+	blockCoinbaseA := "0xaaa0000000000000000000000000000000001350"
+	//Get from block validator error message
+	merkleRoot := "b345a8560bd51926803dd17677c9f0751193914a851a4ec13063d6bf50220b53"
+	parentBlock := CreateBlock(blockchain, config, currentBlock, 1350, 450, blockCoinbaseA, signer, signFn, nil, nil, merkleRoot)
+	err := blockchain.InsertBlock(parentBlock)
+	assert.Nil(t, err)
+	// 1350 is a gap block, need to update the snapshot
+	err = blockchain.UpdateM1()
+	assert.Nil(t, err)
+	// but we wait until 1800 to test the snapshot
+
+	t.Logf("Inserting block from 1351 to 1800...")
+	for i := 1351; i <= 1800; i++ {
+		blockCoinbase := fmt.Sprintf("0xaaa000000000000000000000000000000000%4d", i)
+		block := CreateBlock(blockchain, config, parentBlock, i, int64(i-900), blockCoinbase, signer, signFn, nil, nil, merkleRoot)
+		err = blockchain.InsertBlock(block)
+		assert.Nil(t, err)
+		if i < 1800 {
+			parentBlock = block
+		}
+		if i == 1800 {
+			snap, err := x.GetSnapshot(blockchain, block.Header())
+
+			assert.Nil(t, err)
+			assert.Equal(t, 1350, int(snap.Number))
+			assert.Equal(t, 128, len(snap.NextEpochMasterNodes)) // 128 is all masternode candidates, not limited by MaxMasternodes
+		}
+	}
+
+	tstamp := time.Now().Unix()
+
+	header1800 := &types.Header{
+		ParentHash: parentBlock.Hash(),
+		Number:     big.NewInt(int64(1800)),
+		GasLimit:   params.TargetGasLimit,
+		Time:       big.NewInt(tstamp),
+		Coinbase:   voterAddr,
+	}
+
+	adaptor.EngineV2.SetNewRoundFaker(blockchain, types.Round(900), false)
+	blockInfo := &types.BlockInfo{Hash: parentBlock.Hash(), Round: types.Round(900 - 1), Number: parentBlock.Number()}
+	signature := []byte{1, 2, 3, 4, 5, 6, 7, 8}
+	signatures := []types.Signature{signature}
+	quorumCert := &types.QuorumCert{ProposedBlockInfo: blockInfo, Signatures: signatures, GapNumber: 1350}
+	adaptor.EngineV2.ProcessQCFaker(blockchain, quorumCert)
+	adaptor.EngineV2.AuthorizeFaker(voterAddr)
+	err = adaptor.Prepare(blockchain, header1800)
+	assert.Nil(t, err)
+	assert.Equal(t, common.MaxMasternodesV2, len(header1800.Validators)/common.AddressLength) // although 128 masternode candidates, we can only pick MaxMasternodes
+	assert.Equal(t, 0, len(header1800.Penalties)/common.AddressLength)
+}
diff --git a/consensus/tests/engine_v2_tests/proposed_block_test.go b/consensus/tests/engine_v2_tests/proposed_block_test.go
index db7485911b..3f39a24a66 100644
--- a/consensus/tests/engine_v2_tests/proposed_block_test.go
+++ b/consensus/tests/engine_v2_tests/proposed_block_test.go
@@ -45,7 +45,7 @@ func TestShouldSendVoteMsgAndCommitGrandGrandParentBlock(t *testing.T) {
 	// Insert another Block, but it won't trigger commit
 	blockNum := 902
 	blockCoinBase := fmt.Sprintf("0x111000000000000000000000000000000%03d", blockNum)
-	block902 := CreateBlock(blockchain, params.TestXDPoSMockChainConfig, currentBlock, blockNum, 2, blockCoinBase, signer, signFn, nil, nil)
+	block902 := CreateBlock(blockchain, params.TestXDPoSMockChainConfig, currentBlock, blockNum, 2, blockCoinBase, signer, signFn, nil, nil, "")
 	err = blockchain.InsertBlock(block902)
 	assert.Nil(t, err)
 	err = engineV2.ProposedBlockHandler(blockchain, block902.Header())
@@ -63,7 +63,7 @@ func TestShouldSendVoteMsgAndCommitGrandGrandParentBlock(t *testing.T) {
 	// Insert one more Block, but still won't trigger commit
 	blockNum = 903
 	blockCoinBase = fmt.Sprintf("0x111000000000000000000000000000000%03d", blockNum)
-	block903 := CreateBlock(blockchain, params.TestXDPoSMockChainConfig, block902, blockNum, 3, blockCoinBase, signer, signFn, nil, nil)
+	block903 := CreateBlock(blockchain, params.TestXDPoSMockChainConfig, block902, blockNum, 3, blockCoinBase, signer, signFn, nil, nil, "")
 	err = blockchain.InsertBlock(block903)
 	assert.Nil(t, err)
 	err = engineV2.ProposedBlockHandler(blockchain, block903.Header())
@@ -82,7 +82,7 @@ func TestShouldSendVoteMsgAndCommitGrandGrandParentBlock(t *testing.T) {
 	// Insert one more Block, this time will trigger commit
 	blockNum = 904
 	blockCoinBase = fmt.Sprintf("0x111000000000000000000000000000000%03d", blockNum)
-	block904 := CreateBlock(blockchain, params.TestXDPoSMockChainConfig, block903, blockNum, 4, blockCoinBase, signer, signFn, nil, nil)
+	block904 := CreateBlock(blockchain, params.TestXDPoSMockChainConfig, block903, blockNum, 4, blockCoinBase, signer, signFn, nil, nil, "")
 	err = blockchain.InsertBlock(block904)
 	assert.Nil(t, err)
 	err = engineV2.ProposedBlockHandler(blockchain, block904.Header())
@@ -134,7 +134,7 @@ func TestShouldNotCommitIfRoundsNotContinousFor3Rounds(t *testing.T) {
 	// Injecting new block which have gaps in the round number (Round 7 instead of 6)
 	blockNum := 906
 	blockCoinBase := fmt.Sprintf("0x111000000000000000000000000000000%03d", blockNum)
-	block906 := CreateBlock(blockchain, params.TestXDPoSMockChainConfig, currentBlock, blockNum, 7, blockCoinBase, signer, signFn, nil, nil)
+	block906 := CreateBlock(blockchain, params.TestXDPoSMockChainConfig, currentBlock, blockNum, 7, blockCoinBase, signer, signFn, nil, nil, "")
 	err = blockchain.InsertBlock(block906)
 	assert.Nil(t, err)
 	err = engineV2.ProposedBlockHandler(blockchain, block906.Header())
@@ -156,7 +156,7 @@ func TestShouldNotCommitIfRoundsNotContinousFor3Rounds(t *testing.T) {
 
 	blockNum = 907
 	blockCoinBase = fmt.Sprintf("0x111000000000000000000000000000000%03d", blockNum)
-	block907 := CreateBlock(blockchain, params.TestXDPoSMockChainConfig, block906, blockNum, 8, blockCoinBase, signer, signFn, nil, nil)
+	block907 := CreateBlock(blockchain, params.TestXDPoSMockChainConfig, block906, blockNum, 8, blockCoinBase, signer, signFn, nil, nil, "")
 	err = blockchain.InsertBlock(block907)
 	assert.Nil(t, err)
 	err = engineV2.ProposedBlockHandler(blockchain, block907.Header())
diff --git a/consensus/tests/engine_v2_tests/timeout_test.go b/consensus/tests/engine_v2_tests/timeout_test.go
index 0199249d16..c1c9709d5c 100644
--- a/consensus/tests/engine_v2_tests/timeout_test.go
+++ b/consensus/tests/engine_v2_tests/timeout_test.go
@@ -109,7 +109,7 @@ func TestTimeoutPeriodAndThreadholdConfigChange(t *testing.T) {
 	// Create another block to trigger update parameters
 	blockNum := 1800
 	blockCoinBase := "0x111000000000000000000000000000000123"
-	currentBlock = CreateBlock(blockchain, params.TestXDPoSMockChainConfig, currentBlock, blockNum, 900, blockCoinBase, signer, signFn, nil, nil)
+	currentBlock = CreateBlock(blockchain, params.TestXDPoSMockChainConfig, currentBlock, blockNum, 900, blockCoinBase, signer, signFn, nil, nil, "")
 	currentBlockHeader := currentBlock.Header()
 	currentBlockHeader.Time = big.NewInt(time.Now().Unix())
 	err := blockchain.InsertBlock(currentBlock)
diff --git a/consensus/tests/engine_v2_tests/verify_blockinfo_test.go b/consensus/tests/engine_v2_tests/verify_blockinfo_test.go
index 68778d899d..5bc5a8c45f 100644
--- a/consensus/tests/engine_v2_tests/verify_blockinfo_test.go
+++ b/consensus/tests/engine_v2_tests/verify_blockinfo_test.go
@@ -26,7 +26,7 @@ func TestShouldVerifyBlockInfo(t *testing.T) {
 	// Insert another Block, but it won't trigger commit
 	blockNum := 902
 	blockCoinBase := fmt.Sprintf("0x111000000000000000000000000000000%03d", blockNum)
-	block902 := CreateBlock(blockchain, params.TestXDPoSMockChainConfig, currentBlock, blockNum, 2, blockCoinBase, signer, signFn, nil, nil)
+	block902 := CreateBlock(blockchain, params.TestXDPoSMockChainConfig, currentBlock, blockNum, 2, blockCoinBase, signer, signFn, nil, nil, "")
 	err = blockchain.InsertBlock(block902)
 	assert.Nil(t, err)
 
diff --git a/consensus/tests/engine_v2_tests/verify_header_test.go b/consensus/tests/engine_v2_tests/verify_header_test.go
index 11bb9c1fd3..4e1cb8b7e3 100644
--- a/consensus/tests/engine_v2_tests/verify_header_test.go
+++ b/consensus/tests/engine_v2_tests/verify_header_test.go
@@ -421,12 +421,12 @@ func TestShouldVerifyHeadersEvenIfParentsNotYetWrittenIntoDB(t *testing.T) {
 	// Create block 911 but don't write into DB
 	blockNumber := 911
 	roundNumber := int64(blockNumber) - config.XDPoS.V2.SwitchBlock.Int64()
-	block911 := CreateBlock(blockchain, &config, block910, blockNumber, roundNumber, signer.Hex(), signer, signFn, nil, nil)
+	block911 := CreateBlock(blockchain, &config, block910, blockNumber, roundNumber, signer.Hex(), signer, signFn, nil, nil, "")
 
 	// Create block 912 and not write into DB as well
 	blockNumber = 912
 	roundNumber = int64(blockNumber) - config.XDPoS.V2.SwitchBlock.Int64()
-	block912 := CreateBlock(blockchain, &config, block911, blockNumber, roundNumber, signer.Hex(), signer, signFn, nil, nil)
+	block912 := CreateBlock(blockchain, &config, block911, blockNumber, roundNumber, signer.Hex(), signer, signFn, nil, nil, "")
 
 	headersTobeVerified = append(headersTobeVerified, block910.Header(), block911.Header(), block912.Header())
 	// Randomly set full verify
diff --git a/consensus/tests/engine_v2_tests/vote_test.go b/consensus/tests/engine_v2_tests/vote_test.go
index e9a1041e8a..311e0488eb 100644
--- a/consensus/tests/engine_v2_tests/vote_test.go
+++ b/consensus/tests/engine_v2_tests/vote_test.go
@@ -339,7 +339,7 @@ func TestVoteMessageShallNotThrowErrorIfBlockNotYetExist(t *testing.T) {
 	// Create a new block but don't inject it into the chain yet
 	blockNum := 906
 	blockCoinBase := fmt.Sprintf("0x111000000000000000000000000000000%03d", blockNum)
-	block := CreateBlock(blockchain, params.TestXDPoSMockChainConfig, currentBlock, blockNum, 6, blockCoinBase, signer, signFn, nil, nil)
+	block := CreateBlock(blockchain, params.TestXDPoSMockChainConfig, currentBlock, blockNum, 6, blockCoinBase, signer, signFn, nil, nil, "")
 
 	blockInfo := &types.BlockInfo{
 		Hash:   block.Header().Hash(),
diff --git a/core/blockchain.go b/core/blockchain.go
index 927a3ba4df..0de36014ae 100644
--- a/core/blockchain.go
+++ b/core/blockchain.go
@@ -2550,20 +2550,7 @@ func (bc *BlockChain) UpdateM1() error {
 		log.Info("Updating new set of masternodes")
 		// get block header
 		header := bc.CurrentHeader()
-		var maxMasternodes int
-		// check if block number is increase ms checkpoint
-		if bc.chainConfig.IsTIPIncreaseMasternodes(header.Number) || (bc.chainConfig.XDPoS.V2.SwitchBlock != nil && header.Number.Cmp(bc.chainConfig.XDPoS.V2.SwitchBlock) == 1) {
-			// using new masterndoes
-			maxMasternodes = common.MaxMasternodesV2
-		} else {
-			// using old masterndoes
-			maxMasternodes = common.MaxMasternodes
-		}
-		if len(ms) > maxMasternodes {
-			err = engine.UpdateMasternodes(bc, bc.CurrentHeader(), ms[:maxMasternodes])
-		} else {
-			err = engine.UpdateMasternodes(bc, bc.CurrentHeader(), ms)
-		}
+		err = engine.UpdateMasternodes(bc, header, ms)
 		if err != nil {
 			return err
 		}
diff --git a/eth/backend.go b/eth/backend.go
index a3f09ccac0..91c60d40d9 100644
--- a/eth/backend.go
+++ b/eth/backend.go
@@ -338,7 +338,7 @@ func CreateDB(ctx *node.ServiceContext, config *Config, name string) (ethdb.Data
 func CreateConsensusEngine(ctx *node.ServiceContext, config *ethash.Config, chainConfig *params.ChainConfig, db ethdb.Database) consensus.Engine {
 	// If delegated-proof-of-stake is requested, set it up
 	if chainConfig.XDPoS != nil {
-		return XDPoS.New(chainConfig.XDPoS, db)
+		return XDPoS.New(chainConfig, db)
 	}
 
 	// Otherwise assume proof-of-work