diff --git a/helix-contract/contracts/mapping-token/v3/GuardV3.sol b/helix-contract/contracts/mapping-token/v3/GuardV3.sol
index d0441f3..2715ab6 100644
--- a/helix-contract/contracts/mapping-token/v3/GuardV3.sol
+++ b/helix-contract/contracts/mapping-token/v3/GuardV3.sol
@@ -11,10 +11,10 @@ import "../interfaces/IWToken.sol";
 contract GuardV3 is GuardRegistryV3, Pausable {
     using SafeMath for uint256;
 
-    mapping(uint256 => bytes32) deposits;
+    mapping(uint256 => bytes32) public deposits;
 
     uint256 public maxUnclaimableTime;
-    mapping(address => bool) depositors;
+    mapping(address => bool) public depositors;
     address public operator;
 
     event TokenDeposit(address sender, uint256 id, uint256 timestamp, address token, address recipient, uint256 amount);
diff --git a/helix-contract/flatten/xtoken-v3/GuardV3.sol b/helix-contract/flatten/xtoken-v3/GuardV3.sol
index 5f6d580..497e258 100644
--- a/helix-contract/flatten/xtoken-v3/GuardV3.sol
+++ b/helix-contract/flatten/xtoken-v3/GuardV3.sol
@@ -19,15 +19,6 @@
 
 pragma solidity ^0.8.17;
 
-// File contracts/mapping-token/interfaces/IWToken.sol
-// License-Identifier: MIT
-
-
-interface IWToken {
-    function deposit() external payable;
-    function withdraw(uint wad) external;
-}
-
 // File @zeppelin-solidity/contracts/utils/Strings.sol@v4.7.3
 // License-Identifier: MIT
 // OpenZeppelin Contracts (last updated v4.7.0) (utils/Strings.sol)
@@ -617,6 +608,98 @@ contract GuardRegistryV3 {
     }
 }
 
+// File contracts/mapping-token/interfaces/IWToken.sol
+// License-Identifier: MIT
+
+
+interface IWToken {
+    function deposit() external payable;
+    function withdraw(uint wad) external;
+}
+
+// File @zeppelin-solidity/contracts/token/ERC20/IERC20.sol@v4.7.3
+// License-Identifier: MIT
+// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC20/IERC20.sol)
+
+
+/**
+ * @dev Interface of the ERC20 standard as defined in the EIP.
+ */
+interface IERC20 {
+    /**
+     * @dev Emitted when `value` tokens are moved from one account (`from`) to
+     * another (`to`).
+     *
+     * Note that `value` may be zero.
+     */
+    event Transfer(address indexed from, address indexed to, uint256 value);
+
+    /**
+     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
+     * a call to {approve}. `value` is the new allowance.
+     */
+    event Approval(address indexed owner, address indexed spender, uint256 value);
+
+    /**
+     * @dev Returns the amount of tokens in existence.
+     */
+    function totalSupply() external view returns (uint256);
+
+    /**
+     * @dev Returns the amount of tokens owned by `account`.
+     */
+    function balanceOf(address account) external view returns (uint256);
+
+    /**
+     * @dev Moves `amount` tokens from the caller's account to `to`.
+     *
+     * Returns a boolean value indicating whether the operation succeeded.
+     *
+     * Emits a {Transfer} event.
+     */
+    function transfer(address to, uint256 amount) external returns (bool);
+
+    /**
+     * @dev Returns the remaining number of tokens that `spender` will be
+     * allowed to spend on behalf of `owner` through {transferFrom}. This is
+     * zero by default.
+     *
+     * This value changes when {approve} or {transferFrom} are called.
+     */
+    function allowance(address owner, address spender) external view returns (uint256);
+
+    /**
+     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
+     *
+     * Returns a boolean value indicating whether the operation succeeded.
+     *
+     * IMPORTANT: Beware that changing an allowance with this method brings the risk
+     * that someone may use both the old and the new allowance by unfortunate
+     * transaction ordering. One possible solution to mitigate this race
+     * condition is to first reduce the spender's allowance to 0 and set the
+     * desired value afterwards:
+     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
+     *
+     * Emits an {Approval} event.
+     */
+    function approve(address spender, uint256 amount) external returns (bool);
+
+    /**
+     * @dev Moves `amount` tokens from `from` to `to` using the
+     * allowance mechanism. `amount` is then deducted from the caller's
+     * allowance.
+     *
+     * Returns a boolean value indicating whether the operation succeeded.
+     *
+     * Emits a {Transfer} event.
+     */
+    function transferFrom(
+        address from,
+        address to,
+        uint256 amount
+    ) external returns (bool);
+}
+
 // File @zeppelin-solidity/contracts/utils/Context.sol@v4.7.3
 // License-Identifier: MIT
 // OpenZeppelin Contracts v4.4.1 (utils/Context.sol)
@@ -974,89 +1057,6 @@ library SafeMath {
     }
 }
 
-// File @zeppelin-solidity/contracts/token/ERC20/IERC20.sol@v4.7.3
-// License-Identifier: MIT
-// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC20/IERC20.sol)
-
-
-/**
- * @dev Interface of the ERC20 standard as defined in the EIP.
- */
-interface IERC20 {
-    /**
-     * @dev Emitted when `value` tokens are moved from one account (`from`) to
-     * another (`to`).
-     *
-     * Note that `value` may be zero.
-     */
-    event Transfer(address indexed from, address indexed to, uint256 value);
-
-    /**
-     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
-     * a call to {approve}. `value` is the new allowance.
-     */
-    event Approval(address indexed owner, address indexed spender, uint256 value);
-
-    /**
-     * @dev Returns the amount of tokens in existence.
-     */
-    function totalSupply() external view returns (uint256);
-
-    /**
-     * @dev Returns the amount of tokens owned by `account`.
-     */
-    function balanceOf(address account) external view returns (uint256);
-
-    /**
-     * @dev Moves `amount` tokens from the caller's account to `to`.
-     *
-     * Returns a boolean value indicating whether the operation succeeded.
-     *
-     * Emits a {Transfer} event.
-     */
-    function transfer(address to, uint256 amount) external returns (bool);
-
-    /**
-     * @dev Returns the remaining number of tokens that `spender` will be
-     * allowed to spend on behalf of `owner` through {transferFrom}. This is
-     * zero by default.
-     *
-     * This value changes when {approve} or {transferFrom} are called.
-     */
-    function allowance(address owner, address spender) external view returns (uint256);
-
-    /**
-     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
-     *
-     * Returns a boolean value indicating whether the operation succeeded.
-     *
-     * IMPORTANT: Beware that changing an allowance with this method brings the risk
-     * that someone may use both the old and the new allowance by unfortunate
-     * transaction ordering. One possible solution to mitigate this race
-     * condition is to first reduce the spender's allowance to 0 and set the
-     * desired value afterwards:
-     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
-     *
-     * Emits an {Approval} event.
-     */
-    function approve(address spender, uint256 amount) external returns (bool);
-
-    /**
-     * @dev Moves `amount` tokens from `from` to `to` using the
-     * allowance mechanism. `amount` is then deducted from the caller's
-     * allowance.
-     *
-     * Returns a boolean value indicating whether the operation succeeded.
-     *
-     * Emits a {Transfer} event.
-     */
-    function transferFrom(
-        address from,
-        address to,
-        uint256 amount
-    ) external returns (bool);
-}
-
 // File contracts/mapping-token/v3/GuardV3.sol
 // License-Identifier: Apache-2.0
 
@@ -1068,10 +1068,10 @@ interface IERC20 {
 contract GuardV3 is GuardRegistryV3, Pausable {
     using SafeMath for uint256;
 
-    mapping(uint256 => bytes32) deposits;
+    mapping(uint256 => bytes32) public deposits;
 
     uint256 public maxUnclaimableTime;
-    mapping(address => bool) depositors;
+    mapping(address => bool) public depositors;
     address public operator;
 
     event TokenDeposit(address sender, uint256 id, uint256 timestamp, address token, address recipient, uint256 amount);
diff --git a/helix-contract/flatten/xtoken-v3/MsglineMessager.sol b/helix-contract/flatten/xtoken-v3/MsglineMessager.sol
index 65c8002..eab164b 100644
--- a/helix-contract/flatten/xtoken-v3/MsglineMessager.sol
+++ b/helix-contract/flatten/xtoken-v3/MsglineMessager.sol
@@ -14,7 +14,7 @@
  *  '----------------'  '----------------'  '----------------'  '----------------'  '----------------' '
  * 
  *
- * 12/25/2023
+ * 12/26/2023
  **/
 
 pragma solidity ^0.8.17;
diff --git a/helix-contract/flatten/xtoken-v3/xTokenBacking.sol b/helix-contract/flatten/xtoken-v3/xTokenBacking.sol
index 872ba04..851ce08 100644
--- a/helix-contract/flatten/xtoken-v3/xTokenBacking.sol
+++ b/helix-contract/flatten/xtoken-v3/xTokenBacking.sol
@@ -14,7 +14,7 @@
  *  '----------------'  '----------------'  '----------------'  '----------------'  '----------------' '
  * 
  *
- * 12/25/2023
+ * 12/26/2023
  **/
 
 pragma solidity ^0.8.17;
@@ -160,6 +160,29 @@ interface IWToken {
     function withdraw(uint wad) external;
 }
 
+// File contracts/mapping-token/v3/interfaces/IxTokenIssuing.sol
+// License-Identifier: MIT
+
+interface IxTokenIssuing {
+    function handleIssuingForUnlockFailureFromRemote(
+        uint256 originalChainId,
+        address originalToken,
+        address originalSender,
+        address recipient,
+        uint256 amount,
+        uint256 nonce
+    ) external;
+
+    function issuexToken(
+        uint256 remoteChainId,
+        address originalToken,
+        address originalSender,
+        address recipient,
+        uint256 amount,
+        uint256 nonce
+    ) external;
+}
+
 // File contracts/interfaces/IMessager.sol
 // License-Identifier: MIT
 
@@ -298,6 +321,135 @@ contract DailyLimit {
     }
 }
 
+// File @zeppelin-solidity/contracts/utils/Context.sol@v4.7.3
+// License-Identifier: MIT
+// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)
+
+
+/**
+ * @dev Provides information about the current execution context, including the
+ * sender of the transaction and its data. While these are generally available
+ * via msg.sender and msg.data, they should not be accessed in such a direct
+ * manner, since when dealing with meta-transactions the account sending and
+ * paying for execution may not be the actual sender (as far as an application
+ * is concerned).
+ *
+ * This contract is only required for intermediate, library-like contracts.
+ */
+abstract contract Context {
+    function _msgSender() internal view virtual returns (address) {
+        return msg.sender;
+    }
+
+    function _msgData() internal view virtual returns (bytes calldata) {
+        return msg.data;
+    }
+}
+
+// File @zeppelin-solidity/contracts/security/Pausable.sol@v4.7.3
+// License-Identifier: MIT
+// OpenZeppelin Contracts (last updated v4.7.0) (security/Pausable.sol)
+
+
+/**
+ * @dev Contract module which allows children to implement an emergency stop
+ * mechanism that can be triggered by an authorized account.
+ *
+ * This module is used through inheritance. It will make available the
+ * modifiers `whenNotPaused` and `whenPaused`, which can be applied to
+ * the functions of your contract. Note that they will not be pausable by
+ * simply including this module, only once the modifiers are put in place.
+ */
+abstract contract Pausable is Context {
+    /**
+     * @dev Emitted when the pause is triggered by `account`.
+     */
+    event Paused(address account);
+
+    /**
+     * @dev Emitted when the pause is lifted by `account`.
+     */
+    event Unpaused(address account);
+
+    bool private _paused;
+
+    /**
+     * @dev Initializes the contract in unpaused state.
+     */
+    constructor() {
+        _paused = false;
+    }
+
+    /**
+     * @dev Modifier to make a function callable only when the contract is not paused.
+     *
+     * Requirements:
+     *
+     * - The contract must not be paused.
+     */
+    modifier whenNotPaused() {
+        _requireNotPaused();
+        _;
+    }
+
+    /**
+     * @dev Modifier to make a function callable only when the contract is paused.
+     *
+     * Requirements:
+     *
+     * - The contract must be paused.
+     */
+    modifier whenPaused() {
+        _requirePaused();
+        _;
+    }
+
+    /**
+     * @dev Returns true if the contract is paused, and false otherwise.
+     */
+    function paused() public view virtual returns (bool) {
+        return _paused;
+    }
+
+    /**
+     * @dev Throws if the contract is paused.
+     */
+    function _requireNotPaused() internal view virtual {
+        require(!paused(), "Pausable: paused");
+    }
+
+    /**
+     * @dev Throws if the contract is not paused.
+     */
+    function _requirePaused() internal view virtual {
+        require(paused(), "Pausable: not paused");
+    }
+
+    /**
+     * @dev Triggers stopped state.
+     *
+     * Requirements:
+     *
+     * - The contract must not be paused.
+     */
+    function _pause() internal virtual whenNotPaused {
+        _paused = true;
+        emit Paused(_msgSender());
+    }
+
+    /**
+     * @dev Returns to normal state.
+     *
+     * Requirements:
+     *
+     * - The contract must be paused.
+     */
+    function _unpause() internal virtual whenPaused {
+        _paused = false;
+        emit Unpaused(_msgSender());
+    }
+}
+
 // File @zeppelin-solidity/contracts/utils/Address.sol@v4.7.3
 // License-Identifier: MIT
 // OpenZeppelin Contracts (last updated v4.7.0) (utils/Address.sol)
@@ -658,135 +810,6 @@ abstract contract Initializable {
     }
 }
 
-// File @zeppelin-solidity/contracts/utils/Context.sol@v4.7.3
-// License-Identifier: MIT
-// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)
-
-
-/**
- * @dev Provides information about the current execution context, including the
- * sender of the transaction and its data. While these are generally available
- * via msg.sender and msg.data, they should not be accessed in such a direct
- * manner, since when dealing with meta-transactions the account sending and
- * paying for execution may not be the actual sender (as far as an application
- * is concerned).
- *
- * This contract is only required for intermediate, library-like contracts.
- */
-abstract contract Context {
-    function _msgSender() internal view virtual returns (address) {
-        return msg.sender;
-    }
-
-    function _msgData() internal view virtual returns (bytes calldata) {
-        return msg.data;
-    }
-}
-
-// File @zeppelin-solidity/contracts/security/Pausable.sol@v4.7.3
-// License-Identifier: MIT
-// OpenZeppelin Contracts (last updated v4.7.0) (security/Pausable.sol)
-
-
-/**
- * @dev Contract module which allows children to implement an emergency stop
- * mechanism that can be triggered by an authorized account.
- *
- * This module is used through inheritance. It will make available the
- * modifiers `whenNotPaused` and `whenPaused`, which can be applied to
- * the functions of your contract. Note that they will not be pausable by
- * simply including this module, only once the modifiers are put in place.
- */
-abstract contract Pausable is Context {
-    /**
-     * @dev Emitted when the pause is triggered by `account`.
-     */
-    event Paused(address account);
-
-    /**
-     * @dev Emitted when the pause is lifted by `account`.
-     */
-    event Unpaused(address account);
-
-    bool private _paused;
-
-    /**
-     * @dev Initializes the contract in unpaused state.
-     */
-    constructor() {
-        _paused = false;
-    }
-
-    /**
-     * @dev Modifier to make a function callable only when the contract is not paused.
-     *
-     * Requirements:
-     *
-     * - The contract must not be paused.
-     */
-    modifier whenNotPaused() {
-        _requireNotPaused();
-        _;
-    }
-
-    /**
-     * @dev Modifier to make a function callable only when the contract is paused.
-     *
-     * Requirements:
-     *
-     * - The contract must be paused.
-     */
-    modifier whenPaused() {
-        _requirePaused();
-        _;
-    }
-
-    /**
-     * @dev Returns true if the contract is paused, and false otherwise.
-     */
-    function paused() public view virtual returns (bool) {
-        return _paused;
-    }
-
-    /**
-     * @dev Throws if the contract is paused.
-     */
-    function _requireNotPaused() internal view virtual {
-        require(!paused(), "Pausable: paused");
-    }
-
-    /**
-     * @dev Throws if the contract is not paused.
-     */
-    function _requirePaused() internal view virtual {
-        require(paused(), "Pausable: not paused");
-    }
-
-    /**
-     * @dev Triggers stopped state.
-     *
-     * Requirements:
-     *
-     * - The contract must not be paused.
-     */
-    function _pause() internal virtual whenNotPaused {
-        _paused = true;
-        emit Paused(_msgSender());
-    }
-
-    /**
-     * @dev Returns to normal state.
-     *
-     * Requirements:
-     *
-     * - The contract must be paused.
-     */
-    function _unpause() internal virtual whenPaused {
-        _paused = false;
-        emit Unpaused(_msgSender());
-    }
-}
-
 // File contracts/mapping-token/v3/base/xTokenBridgeBase.sol
 // License-Identifier: MIT
 
@@ -951,29 +974,6 @@ contract xTokenBridgeBase is Initializable, Pausable, AccessController, DailyLim
     }
 }
 
-// File contracts/mapping-token/v3/interfaces/IxTokenIssuing.sol
-// License-Identifier: MIT
-
-interface IxTokenIssuing {
-    function handleIssuingForUnlockFailureFromRemote(
-        uint256 originalChainId,
-        address originalToken,
-        address originalSender,
-        address recipient,
-        uint256 amount,
-        uint256 nonce
-    ) external;
-
-    function issuexToken(
-        uint256 remoteChainId,
-        address originalToken,
-        address originalSender,
-        address recipient,
-        uint256 amount,
-        uint256 nonce
-    ) external;
-}
-
 // File contracts/mapping-token/v3/base/xTokenBacking.sol
 // License-Identifier: MIT
 
diff --git a/helix-contract/flatten/xtoken-v3/xTokenErc20.sol b/helix-contract/flatten/xtoken-v3/xTokenErc20.sol
index c62b02e..ae6d4a3 100644
--- a/helix-contract/flatten/xtoken-v3/xTokenErc20.sol
+++ b/helix-contract/flatten/xtoken-v3/xTokenErc20.sol
@@ -14,7 +14,7 @@
  *  '----------------'  '----------------'  '----------------'  '----------------'  '----------------' '
  * 
  *
- * 12/25/2023
+ * 12/26/2023
  **/
 
 pragma solidity ^0.8.17;
diff --git a/helix-contract/flatten/xtoken-v3/xTokenIssuing.sol b/helix-contract/flatten/xtoken-v3/xTokenIssuing.sol
index 9ee81cd..4487af7 100644
--- a/helix-contract/flatten/xtoken-v3/xTokenIssuing.sol
+++ b/helix-contract/flatten/xtoken-v3/xTokenIssuing.sol
@@ -14,7 +14,7 @@
  *  '----------------'  '----------------'  '----------------'  '----------------'  '----------------' '
  * 
  *
- * 12/25/2023
+ * 12/26/2023
  **/
 
 pragma solidity ^0.8.17;
@@ -151,48 +151,6 @@ interface IGuard {
   function deposit(uint256 id, address token, address recipient, uint256 amount) external;
 }
 
-// File contracts/utils/AccessController.sol
-// License-Identifier: MIT
-
-/// @title AccessController
-/// @notice AccessController is a contract to control the access permission 
-/// @dev See https://github.com/helix-bridge/contracts/tree/master/helix-contract
-contract AccessController {
-    address public dao;
-    address public operator;
-    address public pendingDao;
-
-    modifier onlyDao() {
-        require(msg.sender == dao, "!dao");
-        _;
-    }
-
-    modifier onlyOperator() {
-        require(msg.sender == operator, "!operator");
-        _;
-    }
-
-    function _initialize(address _dao) internal {
-        dao = _dao;
-        operator = _dao;
-    }
-
-    function setOperator(address _operator) onlyDao external {
-        operator = _operator;
-    }
-
-    function transferOwnership(address _dao) onlyDao external {
-        pendingDao = _dao;
-    }
-
-    function acceptOwnership() external {
-        address newDao = msg.sender;
-        require(pendingDao == newDao, "!pendingDao");
-        delete pendingDao;
-        dao = newDao;
-    }
-}
-
 // File contracts/interfaces/IMessager.sol
 // License-Identifier: MIT
 
@@ -289,132 +247,45 @@ contract DailyLimit {
     }
 }
 
-// File @zeppelin-solidity/contracts/utils/Context.sol@v4.7.3
-// License-Identifier: MIT
-// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)
-
-
-/**
- * @dev Provides information about the current execution context, including the
- * sender of the transaction and its data. While these are generally available
- * via msg.sender and msg.data, they should not be accessed in such a direct
- * manner, since when dealing with meta-transactions the account sending and
- * paying for execution may not be the actual sender (as far as an application
- * is concerned).
- *
- * This contract is only required for intermediate, library-like contracts.
- */
-abstract contract Context {
-    function _msgSender() internal view virtual returns (address) {
-        return msg.sender;
-    }
-
-    function _msgData() internal view virtual returns (bytes calldata) {
-        return msg.data;
-    }
-}
-
-// File @zeppelin-solidity/contracts/security/Pausable.sol@v4.7.3
+// File contracts/utils/AccessController.sol
 // License-Identifier: MIT
-// OpenZeppelin Contracts (last updated v4.7.0) (security/Pausable.sol)
-
 
-/**
- * @dev Contract module which allows children to implement an emergency stop
- * mechanism that can be triggered by an authorized account.
- *
- * This module is used through inheritance. It will make available the
- * modifiers `whenNotPaused` and `whenPaused`, which can be applied to
- * the functions of your contract. Note that they will not be pausable by
- * simply including this module, only once the modifiers are put in place.
- */
-abstract contract Pausable is Context {
-    /**
-     * @dev Emitted when the pause is triggered by `account`.
-     */
-    event Paused(address account);
-
-    /**
-     * @dev Emitted when the pause is lifted by `account`.
-     */
-    event Unpaused(address account);
-
-    bool private _paused;
-
-    /**
-     * @dev Initializes the contract in unpaused state.
-     */
-    constructor() {
-        _paused = false;
-    }
+/// @title AccessController
+/// @notice AccessController is a contract to control the access permission 
+/// @dev See https://github.com/helix-bridge/contracts/tree/master/helix-contract
+contract AccessController {
+    address public dao;
+    address public operator;
+    address public pendingDao;
 
-    /**
-     * @dev Modifier to make a function callable only when the contract is not paused.
-     *
-     * Requirements:
-     *
-     * - The contract must not be paused.
-     */
-    modifier whenNotPaused() {
-        _requireNotPaused();
+    modifier onlyDao() {
+        require(msg.sender == dao, "!dao");
         _;
     }
 
-    /**
-     * @dev Modifier to make a function callable only when the contract is paused.
-     *
-     * Requirements:
-     *
-     * - The contract must be paused.
-     */
-    modifier whenPaused() {
-        _requirePaused();
+    modifier onlyOperator() {
+        require(msg.sender == operator, "!operator");
         _;
     }
 
-    /**
-     * @dev Returns true if the contract is paused, and false otherwise.
-     */
-    function paused() public view virtual returns (bool) {
-        return _paused;
-    }
-
-    /**
-     * @dev Throws if the contract is paused.
-     */
-    function _requireNotPaused() internal view virtual {
-        require(!paused(), "Pausable: paused");
+    function _initialize(address _dao) internal {
+        dao = _dao;
+        operator = _dao;
     }
 
-    /**
-     * @dev Throws if the contract is not paused.
-     */
-    function _requirePaused() internal view virtual {
-        require(paused(), "Pausable: not paused");
+    function setOperator(address _operator) onlyDao external {
+        operator = _operator;
     }
 
-    /**
-     * @dev Triggers stopped state.
-     *
-     * Requirements:
-     *
-     * - The contract must not be paused.
-     */
-    function _pause() internal virtual whenNotPaused {
-        _paused = true;
-        emit Paused(_msgSender());
+    function transferOwnership(address _dao) onlyDao external {
+        pendingDao = _dao;
     }
 
-    /**
-     * @dev Returns to normal state.
-     *
-     * Requirements:
-     *
-     * - The contract must be paused.
-     */
-    function _unpause() internal virtual whenPaused {
-        _paused = false;
-        emit Unpaused(_msgSender());
+    function acceptOwnership() external {
+        address newDao = msg.sender;
+        require(pendingDao == newDao, "!pendingDao");
+        delete pendingDao;
+        dao = newDao;
     }
 }
 
@@ -778,6 +649,135 @@ abstract contract Initializable {
     }
 }
 
+// File @zeppelin-solidity/contracts/utils/Context.sol@v4.7.3
+// License-Identifier: MIT
+// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)
+
+
+/**
+ * @dev Provides information about the current execution context, including the
+ * sender of the transaction and its data. While these are generally available
+ * via msg.sender and msg.data, they should not be accessed in such a direct
+ * manner, since when dealing with meta-transactions the account sending and
+ * paying for execution may not be the actual sender (as far as an application
+ * is concerned).
+ *
+ * This contract is only required for intermediate, library-like contracts.
+ */
+abstract contract Context {
+    function _msgSender() internal view virtual returns (address) {
+        return msg.sender;
+    }
+
+    function _msgData() internal view virtual returns (bytes calldata) {
+        return msg.data;
+    }
+}
+
+// File @zeppelin-solidity/contracts/security/Pausable.sol@v4.7.3
+// License-Identifier: MIT
+// OpenZeppelin Contracts (last updated v4.7.0) (security/Pausable.sol)
+
+
+/**
+ * @dev Contract module which allows children to implement an emergency stop
+ * mechanism that can be triggered by an authorized account.
+ *
+ * This module is used through inheritance. It will make available the
+ * modifiers `whenNotPaused` and `whenPaused`, which can be applied to
+ * the functions of your contract. Note that they will not be pausable by
+ * simply including this module, only once the modifiers are put in place.
+ */
+abstract contract Pausable is Context {
+    /**
+     * @dev Emitted when the pause is triggered by `account`.
+     */
+    event Paused(address account);
+
+    /**
+     * @dev Emitted when the pause is lifted by `account`.
+     */
+    event Unpaused(address account);
+
+    bool private _paused;
+
+    /**
+     * @dev Initializes the contract in unpaused state.
+     */
+    constructor() {
+        _paused = false;
+    }
+
+    /**
+     * @dev Modifier to make a function callable only when the contract is not paused.
+     *
+     * Requirements:
+     *
+     * - The contract must not be paused.
+     */
+    modifier whenNotPaused() {
+        _requireNotPaused();
+        _;
+    }
+
+    /**
+     * @dev Modifier to make a function callable only when the contract is paused.
+     *
+     * Requirements:
+     *
+     * - The contract must be paused.
+     */
+    modifier whenPaused() {
+        _requirePaused();
+        _;
+    }
+
+    /**
+     * @dev Returns true if the contract is paused, and false otherwise.
+     */
+    function paused() public view virtual returns (bool) {
+        return _paused;
+    }
+
+    /**
+     * @dev Throws if the contract is paused.
+     */
+    function _requireNotPaused() internal view virtual {
+        require(!paused(), "Pausable: paused");
+    }
+
+    /**
+     * @dev Throws if the contract is not paused.
+     */
+    function _requirePaused() internal view virtual {
+        require(paused(), "Pausable: not paused");
+    }
+
+    /**
+     * @dev Triggers stopped state.
+     *
+     * Requirements:
+     *
+     * - The contract must not be paused.
+     */
+    function _pause() internal virtual whenNotPaused {
+        _paused = true;
+        emit Paused(_msgSender());
+    }
+
+    /**
+     * @dev Returns to normal state.
+     *
+     * Requirements:
+     *
+     * - The contract must be paused.
+     */
+    function _unpause() internal virtual whenPaused {
+        _paused = false;
+        emit Unpaused(_msgSender());
+    }
+}
+
 // File contracts/mapping-token/v3/base/xTokenBridgeBase.sol
 // License-Identifier: MIT