diff --git a/node/core/config.go b/node/core/config.go
index dbd6e19ca..8ce2f58c7 100644
--- a/node/core/config.go
+++ b/node/core/config.go
@@ -23,6 +23,8 @@ import (
 )
 
 var (
+	MainnetBlsKeyCheckForkHeight uint64 = 18409547
+
 	// L1 Mainnet Contract Addresses
 	MainnetRollupContractAddress = common.HexToAddress("0x759894ced0e6af42c26668076ffa84d02e3cef60")
 )
@@ -33,6 +35,7 @@ type Config struct {
 	SequencerAddress              common.Address  `json:"sequencer_address"`
 	L2StakingAddress              common.Address  `json:"l2staking_address"`
 	MaxL1MessageNumPerBlock       uint64          `json:"max_l1_message_num_per_block"`
+	BlsKeyCheckForkHeight         uint64          `json:"bls_key_check_fork_height"`
 	DevSequencer                  bool            `json:"dev_sequencer"`
 	Logger                        tmlog.Logger    `json:"logger"`
 }
@@ -146,5 +149,10 @@ func (c *Config) SetCliContext(ctx *cli.Context) error {
 		c.DevSequencer = ctx.GlobalBool(flags.DevSequencer.Name)
 	}
 
+	if ctx.GlobalIsSet(flags.MainnetFlag.Name) {
+		c.BlsKeyCheckForkHeight = MainnetBlsKeyCheckForkHeight
+		logger.Info("mainnet historical validator compatibility enabled", "BlsKeyCheckForkHeight", c.BlsKeyCheckForkHeight)
+	}
+
 	return nil
 }
diff --git a/node/core/executor.go b/node/core/executor.go
index fa8bf0a88..086703e1b 100644
--- a/node/core/executor.go
+++ b/node/core/executor.go
@@ -45,6 +45,8 @@ type Executor struct {
 	isSequencer    bool
 	devSequencer   bool
 
+	blsKeyCheckForkHeight uint64
+
 	logger  tmlog.Logger
 	metrics *Metrics
 }
@@ -90,17 +92,18 @@ func NewExecutor(newSyncFunc NewSyncerFunc, config *Config, tmPubKey crypto.PubK
 		tmPubKeyBytes = tmPubKey.Bytes()
 	}
 	executor := &Executor{
-		l2Client:            l2Client,
-		bc:                  &Version1Converter{},
-		sequencerCaller:     sequencer,
-		l2StakingCaller:     l2Staking,
-		tmPubKey:            tmPubKeyBytes,
-		nextL1MsgIndex:      index,
-		maxL1MsgNumPerBlock: config.MaxL1MessageNumPerBlock,
-		newSyncerFunc:       newSyncFunc,
-		devSequencer:        config.DevSequencer,
-		logger:              logger,
-		metrics:             PrometheusMetrics("morphnode"),
+		l2Client:              l2Client,
+		bc:                    &Version1Converter{},
+		sequencerCaller:       sequencer,
+		l2StakingCaller:       l2Staking,
+		tmPubKey:              tmPubKeyBytes,
+		nextL1MsgIndex:        index,
+		maxL1MsgNumPerBlock:   config.MaxL1MessageNumPerBlock,
+		newSyncerFunc:         newSyncFunc,
+		devSequencer:          config.DevSequencer,
+		blsKeyCheckForkHeight: config.BlsKeyCheckForkHeight,
+		logger:                logger,
+		metrics:               PrometheusMetrics("morphnode"),
 	}
 
 	if config.DevSequencer {
@@ -356,6 +359,10 @@ func (e *Executor) getValidatorsAtHeight(height int64) ([][]byte, error) {
 	}
 	newValidators := make([][]byte, 0, len(addrs))
 	for i := range stakesInfo {
+		if !e.shouldKeepSequencerAtHeight(uint64(height), stakesInfo[i].BlsKey) {
+			e.logger.Error("getValidatorsAtHeight: skip sequencer with invalid bls key", "height", height, "addr", stakesInfo[i].Addr)
+			continue
+		}
 		newValidators = append(newValidators, stakesInfo[i].TmKey[:])
 	}
 	return newValidators, nil
diff --git a/node/core/sequencers.go b/node/core/sequencers.go
index e56b522b3..4c43a8cf6 100644
--- a/node/core/sequencers.go
+++ b/node/core/sequencers.go
@@ -5,6 +5,7 @@ import (
 	"slices"
 
 	"github.com/morph-l2/go-ethereum/common"
+	"github.com/morph-l2/go-ethereum/crypto/bls12381"
 	"github.com/tendermint/tendermint/crypto/ed25519"
 )
 
@@ -15,7 +16,7 @@ func (e *Executor) sequencerSetUpdates(height uint64) ([][]byte, error) {
 	if err != nil {
 		return nil, err
 	}
-	if e.currentSeqHash != nil && bytes.Equal(e.currentSeqHash[:], seqHash[:]) {
+	if e.shouldReuseSequencerCache(height, seqHash) {
 		return e.nextValidators, nil
 	}
 
@@ -49,6 +50,10 @@ func (e *Executor) sequencerSetUpdates(height uint64) ([][]byte, error) {
 	seqTmKeySet := make(map[[tmKeySize]byte]struct{}, len(stakesInfo))
 	nextValidators := make([][]byte, 0, len(sequencerSet2))
 	for i := range stakesInfo {
+		if !e.shouldKeepSequencerAtHeight(height, stakesInfo[i].BlsKey) {
+			e.logger.Error("sequencerSetUpdates: skip sequencer with invalid bls key", "height", height, "addr", stakesInfo[i].Addr)
+			continue
+		}
 		// sequencerSet2 is the latest updated sequencer set which is considered as the next validator set for tendermint
 		if slices.Contains(sequencerSet2, stakesInfo[i].Addr) {
 			nextValidators = append(nextValidators, stakesInfo[i].TmKey[:])
@@ -63,6 +68,26 @@ func (e *Executor) sequencerSetUpdates(height uint64) ([][]byte, error) {
 	return nextValidators, nil
 }
 
+func (e *Executor) shouldReuseSequencerCache(height uint64, seqHash [32]byte) bool {
+	if e.currentSeqHash == nil || !bytes.Equal(e.currentSeqHash[:], seqHash[:]) {
+		return false
+	}
+
+	if e.blsKeyCheckForkHeight > 0 &&
+		(height == e.blsKeyCheckForkHeight || height == e.blsKeyCheckForkHeight+1) {
+		return false
+	}
+	return true
+}
+
+func (e *Executor) shouldKeepSequencerAtHeight(height uint64, blsKey []byte) bool {
+	if isValidBlsKey(blsKey) {
+		return true
+	}
+
+	return e.blsKeyCheckForkHeight > 0 && height <= e.blsKeyCheckForkHeight
+}
+
 func (e *Executor) updateSequencerSet(height uint64) ([][]byte, error) {
 	validatorUpdates, err := e.sequencerSetUpdates(height)
 	if err != nil {
@@ -94,3 +119,8 @@ func (e *Executor) updateSequencerSet(height uint64) ([][]byte, error) {
 	e.isSequencer = isSequencer
 	return validatorUpdates, nil
 }
+
+func isValidBlsKey(in []byte) bool {
+	_, err := bls12381.NewG2().DecodePoint(in)
+	return err == nil
+}