diff --git a/helix-contract/contracts/mapping-token/v3/xTokenBridge.sol.bak b/helix-contract/contracts/mapping-token/v3/xTokenBridge.sol.bak
deleted file mode 100644
index 943b7bf1..00000000
--- a/helix-contract/contracts/mapping-token/v3/xTokenBridge.sol.bak
+++ /dev/null
@@ -1,172 +0,0 @@
-// SPDX-License-Identifier: MIT
-pragma solidity ^0.8.17;
-
-import "./base/xTokenBacking.sol";
-import "./base/xTokenIssuing.sol";
-import "./interfaces/IMessager.sol";
-import "../../utils/AccessController.sol";
-import "../../utils/DailyLimit.sol";
-
-contract xTokenMessageLineMessager is Application {
-    struct RemoteBridgeInfo {
-        address messager;
-        address tokenBridge;
-    }
-
-    string public version;
-    uint256 public protocolFee;
-    // remoteChainId => info
-    mapping(uint256 => RemoteBridgeInfo) bridges;
-
-    // common method
-    modifier calledByMessager() {
-        uint256 _remoteChainId = _fromChainId();
-        RemoteBridgeInfo memory bridgeInfo = bridges[_remoteChainId];
-        require(msg.sender == bridgeInfo.messager, "invalid msg sender");
-        require(_xmsgSender() == bridgeInfo.tokenBridge, "invalid source msg sender");
-        _;
-    }
-
-    function withdrawProtocolFee(address _receiver, uint256 _amount) external onlyDao {
-        require(_amount <= protocolFee, "not enough fee");
-        TokenTransferHelper.safeTransferNative(_receiver, _amount);
-    }
-
-    function totalFee(uint256 _remoteChainId, bytes memory _payload, bytes memory _extParams) external returns(uint256) {
-        RemoteBridgeInfo memory bridgeInfo = bridges[_remoteChainId];
-        require(bridgeInfo.messager != address(0), "bridge not configured");
-        return IMessager(bridgeInfo.messager).fee(_remoteChainId, bridgeInfo.tokenBridge, _payload, _extParams) + protocolFee;
-    }
-
-    function _sendMessage(
-        uint256 _remoteChainId,
-        bytes memory _payload,
-        uint256 feePrepaid,
-        bytes memory _extParams
-    ) internal whenNotPaused override returns(bytes32 messageId, uint256 fee) {
-        RemoteBridgeInfo memory bridgeInfo = bridges[_remoteChainId];
-        require(bridgeInfo.messager != address(0), "bridge not configured");
-        fee = IMessager(bridgeInfo.messager).fee(_remoteChainId, bridgeInfo.tokenBridge, _payload, _extParams);
-        IMessager(bridgeInfo.messager).send{value: feePrepaid - fee - protocolFee}(
-            _remoteChainId,
-            bridgeInfo.tokenBridge,
-            _payload,
-            _extParams
-        );
-        messageId = IMessager(bridgeInfo.messager).sentMessageId();
-    }
-
-    function _assertMessageIsDelivered(uint256 _remoteChainId, bytes32 _transferId) internal override {
-        RemoteBridgeInfo memory bridgeInfo = bridges[_remoteChainId];
-        require(bridgeInfo.messager != address(0), "bridge not configured");
-        require(IMessager(bridgeInfo.messager).dones(_transferId), "message not delivered");
-    }
-
-    function _messageId() internal returns(bytes32) {
-        return IMessager(msg.sender).recvMessageId();
-    }
-
-    function _version() internal returns(string memory) {
-        return version;
-    }
-
-    // settings
-    function updateBackingGuard(address _guard) external onlyDao {
-        _updateBackingGuard(_guard);
-    }
-
-    function updateIssuingGuard(address _guard) external onlyDao {
-        _updateIssuingGuard(_guard);
-    }
-
-    function registerOriginalToken(
-        uint256 _remoteChainId,
-        address _originalToken,
-        address _xToken
-    ) external onlyDao {
-        _registerOriginalToken(_remoteChainId, _originalToken, _xToken);
-    }
-
-    function registerxToken(
-        uint256 _originalChainId,
-        address _originalToken,
-        string memory _originalChainName,
-        string memory _name,
-        string memory _symbol,
-        uint8 _decimals,
-        uint256 _dailyLimit
-    ) external onlyDao {
-        address xToken = _registerxToken(
-            _originalChainId,
-            _originalToken,
-            _originalChainName,
-            _name,
-            _symbol,
-            _decimals
-        );
-        _setDailyLimit(xToken, _dailyLimit);
-    }
-
-    function updatexToken(
-        uint256 _originalChainId,
-        address _originalToken,
-        address _xToken
-    ) external onlyDao {
-        _updatexToken(_originalChainId, _originalToken, _xToken);
-    }
-
-    function setDailyLimit(address _token, uint256 _dailyLimit) external onlyDao {
-        _setDailyLimit(_token, _dailyLimit);
-    }
-
-    // in backing contract, it only know the original token info
-    // in issuing contract, it know the mapping relationship of original token and it's mapping token xToken
-    // we use original token info in messages
-
-    // method for backing
-    // receive unlock original token message from remote issuing contract
-    function unlockFromRemote(
-        address _originalToken,
-        address _recipient,
-        uint256 _amount
-    ) external calledByMessager whenNotPaused {
-        bytes32 transferId = _messageId();
-        _unlockFromRemote(_fromChainId(), transferId, _originalToken, _recipient, _amount);
-    }
-
-    // when lock and issuing failed
-    // receive unlock(refund) message from remote issuing contract
-    // this will refund original token to original sender
-    function handleUnlockForIssuingFailureFromRemote(
-        address _originalToken,
-        address _originalSender,
-        uint256 _amount
-    ) external calledByMessager whenNotPaused {
-        bytes32 transferId = _messageId();
-        _handleUnlockForIssuingFailureFromRemote(_fromChainId(), transferId, _originalToken, _originalSender, _amount);
-    }
-
-    // method for issuing
-    // receive issuing xToken message from remote backing contract
-    function issuexToken(
-        address _originalToken,
-        address _recipient,
-        uint256 _amount
-    ) external calledByMessager whenNotPaused {
-        bytes32 transferId = _messageId();
-        _issuexToken(_fromChainId(), transferId, _originalToken, _recipient, _amount);
-    }
-
-    // when burn and unlock failed
-    // receive reIssue(refund) message from remote backing contract
-    // this will refund xToken to original sender
-    function handleIssuingForUnlockFailureFromRemote(
-        address _originalToken,
-        address _originalSender,
-        uint256 _amount
-    ) external calledByMessager whenNotPaused {
-        bytes32 transferId = _messageId();
-        _handleIssuingForUnlockFailureFromRemote(_fromChainId(), transferId, _originalToken, _originalSender, _amount);
-    }
-}
-