diff --git a/contracts/BC_fusion/BSCGovernor.sol b/contracts/BSCGovernor.sol
similarity index 99%
rename from contracts/BC_fusion/BSCGovernor.sol
rename to contracts/BSCGovernor.sol
index be520d63..8eae46f7 100644
--- a/contracts/BC_fusion/BSCGovernor.sol
+++ b/contracts/BSCGovernor.sol
@@ -9,13 +9,13 @@ import "@openzeppelin/contracts-upgradeable/governance/extensions/GovernorTimelo
 import "@openzeppelin/contracts-upgradeable/governance/extensions/GovernorVotesQuorumFractionUpgradeable.sol";
 import "@openzeppelin/contracts-upgradeable/governance/extensions/GovernorPreventLateQuorumUpgradeable.sol";
 
-import "./System.sol";
+import "./SystemV2.sol";
 import "./extension/Protectable.sol";
-import "./lib/Utils.sol";
-import "./interface/IGovToken.sol";
+import "./lib/0.8.x/Utils.sol";
+import "./interface/0.8.x/IGovToken.sol";
 
 contract BSCGovernor is
-    System,
+    SystemV2,
     Initializable,
     Protectable,
     GovernorUpgradeable,
diff --git a/contracts/BC_fusion/BSCTimelock.sol b/contracts/BSCTimelock.sol
similarity index 90%
rename from contracts/BC_fusion/BSCTimelock.sol
rename to contracts/BSCTimelock.sol
index b01dfa3a..3049069b 100644
--- a/contracts/BC_fusion/BSCTimelock.sol
+++ b/contracts/BSCTimelock.sol
@@ -3,10 +3,10 @@ pragma solidity 0.8.17;
 
 import "@openzeppelin/contracts-upgradeable/governance/TimelockControllerUpgradeable.sol";
 
-import "./System.sol";
-import "./lib/Utils.sol";
+import "./SystemV2.sol";
+import "./lib/0.8.x/Utils.sol";
 
-contract BSCTimelock is System, Initializable, TimelockControllerUpgradeable {
+contract BSCTimelock is SystemV2, Initializable, TimelockControllerUpgradeable {
     using Utils for bytes;
     using Utils for string;
 
diff --git a/contracts/BSCValidatorSet.sol b/contracts/BSCValidatorSet.sol
index fbc92601..07988d5f 100644
--- a/contracts/BSCValidatorSet.sol
+++ b/contracts/BSCValidatorSet.sol
@@ -2,20 +2,20 @@ pragma solidity 0.6.4;
 pragma experimental ABIEncoderV2;
 
 import "./System.sol";
-import "./lib/BytesLib.sol";
-import "./lib/BytesToTypes.sol";
-import "./lib/Memory.sol";
-import "./interface/ILightClient.sol";
-import "./interface/ISlashIndicator.sol";
-import "./interface/ITokenHub.sol";
-import "./interface/IRelayerHub.sol";
-import "./interface/IParamSubscriber.sol";
-import "./interface/IBSCValidatorSet.sol";
-import "./interface/IApplication.sol";
-import "./interface/IStakeHub.sol";
-import "./lib/SafeMath.sol";
-import "./lib/RLPDecode.sol";
-import "./lib/CmnPkg.sol";
+import "./lib/0.6.x/BytesLib.sol";
+import "./lib/0.6.x/BytesToTypes.sol";
+import "./lib/0.6.x/Memory.sol";
+import "./interface/0.6.x/ILightClient.sol";
+import "./interface/0.6.x/ISlashIndicator.sol";
+import "./interface/0.6.x/ITokenHub.sol";
+import "./interface/0.6.x/IRelayerHub.sol";
+import "./interface/0.6.x/IParamSubscriber.sol";
+import "./interface/0.6.x/IBSCValidatorSet.sol";
+import "./interface/0.6.x/IApplication.sol";
+import "./interface/0.6.x/IStakeHub.sol";
+import "./lib/0.6.x/SafeMath.sol";
+import "./lib/0.6.x/RLPDecode.sol";
+import "./lib/0.6.x/CmnPkg.sol";
 
 interface ICrossChain {
     function registeredContractChannelMap(address, uint8) external view returns (bool);
diff --git a/contracts/GovHub.sol b/contracts/GovHub.sol
index 5223e552..7c50eef7 100644
--- a/contracts/GovHub.sol
+++ b/contracts/GovHub.sol
@@ -1,13 +1,13 @@
 pragma solidity 0.6.4;
 
 import "./System.sol";
-import "./lib/BytesToTypes.sol";
-import "./lib/Memory.sol";
-import "./lib/BytesLib.sol";
-import "./interface/IParamSubscriber.sol";
-import "./interface/IApplication.sol";
-import "./lib/RLPDecode.sol";
-import "./lib/CmnPkg.sol";
+import "./lib/0.6.x/BytesToTypes.sol";
+import "./lib/0.6.x/Memory.sol";
+import "./lib/0.6.x/BytesLib.sol";
+import "./interface/0.6.x/IParamSubscriber.sol";
+import "./interface/0.6.x/IApplication.sol";
+import "./lib/0.6.x/RLPDecode.sol";
+import "./lib/0.6.x/CmnPkg.sol";
 
 contract GovHub is System, IApplication {
     using RLPDecode for *;
diff --git a/contracts/BC_fusion/GovToken.sol b/contracts/GovToken.sol
similarity index 98%
rename from contracts/BC_fusion/GovToken.sol
rename to contracts/GovToken.sol
index f0736b2c..05bbebce 100644
--- a/contracts/BC_fusion/GovToken.sol
+++ b/contracts/GovToken.sol
@@ -6,11 +6,11 @@ import "@openzeppelin/contracts-upgradeable/token/ERC20/extensions/ERC20Burnable
 import "@openzeppelin/contracts-upgradeable/token/ERC20/extensions/ERC20PermitUpgradeable.sol";
 import "@openzeppelin/contracts-upgradeable/token/ERC20/extensions/ERC20VotesUpgradeable.sol";
 
-import "./System.sol";
-import "./interface/IStakeCredit.sol";
+import "./SystemV2.sol";
+import "./interface/0.8.x/IStakeCredit.sol";
 
 contract GovToken is
-    System,
+    SystemV2,
     Initializable,
     ERC20Upgradeable,
     ERC20BurnableUpgradeable,
diff --git a/contracts/SlashIndicator.sol b/contracts/SlashIndicator.sol
index 6b1d47f1..b1897f0d 100644
--- a/contracts/SlashIndicator.sol
+++ b/contracts/SlashIndicator.sol
@@ -2,19 +2,19 @@ pragma solidity 0.6.4;
 pragma experimental ABIEncoderV2;
 
 import "./System.sol";
-import "./lib/BytesToTypes.sol";
-import "./lib/TypesToBytes.sol";
-import "./lib/BytesLib.sol";
-import "./lib/Memory.sol";
-import "./interface/ISlashIndicator.sol";
-import "./interface/IApplication.sol";
-import "./interface/IBSCValidatorSet.sol";
-import "./interface/IParamSubscriber.sol";
-import "./interface/ICrossChain.sol";
-import "./interface/ISystemReward.sol";
-import "./interface/IStakeHub.sol";
-import "./lib/CmnPkg.sol";
-import "./lib/RLPEncode.sol";
+import "./lib/0.6.x/BytesToTypes.sol";
+import "./lib/0.6.x/TypesToBytes.sol";
+import "./lib/0.6.x/BytesLib.sol";
+import "./lib/0.6.x/Memory.sol";
+import "./interface/0.6.x/ISlashIndicator.sol";
+import "./interface/0.6.x/IApplication.sol";
+import "./interface/0.6.x/IBSCValidatorSet.sol";
+import "./interface/0.6.x/IParamSubscriber.sol";
+import "./interface/0.6.x/ICrossChain.sol";
+import "./interface/0.6.x/ISystemReward.sol";
+import "./interface/0.6.x/IStakeHub.sol";
+import "./lib/0.6.x/CmnPkg.sol";
+import "./lib/0.6.x/RLPEncode.sol";
 
 contract SlashIndicator is ISlashIndicator, System, IParamSubscriber, IApplication {
     using RLPEncode for *;
diff --git a/contracts/BC_fusion/StakeCredit.sol b/contracts/StakeCredit.sol
similarity index 98%
rename from contracts/BC_fusion/StakeCredit.sol
rename to contracts/StakeCredit.sol
index 5bd41923..b9c727b2 100644
--- a/contracts/BC_fusion/StakeCredit.sol
+++ b/contracts/StakeCredit.sol
@@ -6,10 +6,10 @@ import "@openzeppelin/contracts-upgradeable/token/ERC20/ERC20Upgradeable.sol";
 import "@openzeppelin/contracts-upgradeable/utils/CountersUpgradeable.sol";
 import "@openzeppelin/contracts-upgradeable/utils/structs/DoubleEndedQueueUpgradeable.sol";
 
-import "./System.sol";
-import "./interface/IStakeHub.sol";
+import "./SystemV2.sol";
+import "./interface/0.8.x/IStakeHub.sol";
 
-contract StakeCredit is System, Initializable, ReentrancyGuardUpgradeable, ERC20Upgradeable {
+contract StakeCredit is SystemV2, Initializable, ReentrancyGuardUpgradeable, ERC20Upgradeable {
     using CountersUpgradeable for CountersUpgradeable.Counter;
     using DoubleEndedQueueUpgradeable for DoubleEndedQueueUpgradeable.Bytes32Deque;
 
diff --git a/contracts/BC_fusion/StakeHub.sol b/contracts/StakeHub.sol
similarity index 99%
rename from contracts/BC_fusion/StakeHub.sol
rename to contracts/StakeHub.sol
index 957e1856..9a873691 100644
--- a/contracts/BC_fusion/StakeHub.sol
+++ b/contracts/StakeHub.sol
@@ -5,17 +5,17 @@ import "@openzeppelin/contracts/proxy/transparent/TransparentUpgradeableProxy.so
 import "@openzeppelin/contracts/utils/structs/EnumerableSet.sol";
 import "@openzeppelin/contracts-upgradeable/proxy/utils/Initializable.sol";
 
-import "./System.sol";
+import "./SystemV2.sol";
 import "./extension/Protectable.sol";
-import "./interface/IBSCValidatorSet.sol";
-import "./interface/ICrossChain.sol";
-import "./interface/IGovToken.sol";
-import "./interface/IStakeCredit.sol";
-import "./interface/ITokenHub.sol";
-import "./lib/RLPDecode.sol";
-import "./lib/Utils.sol";
-
-contract StakeHub is System, Initializable, Protectable {
+import "./interface/0.8.x/IBSCValidatorSet.sol";
+import "./interface/0.8.x/ICrossChain.sol";
+import "./interface/0.8.x/IGovToken.sol";
+import "./interface/0.8.x/IStakeCredit.sol";
+import "./interface/0.8.x/ITokenHub.sol";
+import "./lib/0.8.x/RLPDecode.sol";
+import "./lib/0.8.x/Utils.sol";
+
+contract StakeHub is SystemV2, Initializable, Protectable {
     using RLPDecode for *;
     using Utils for string;
     using Utils for bytes;
diff --git a/contracts/System.sol b/contracts/System.sol
index 45dfc87c..10eb27bc 100644
--- a/contracts/System.sol
+++ b/contracts/System.sol
@@ -1,8 +1,8 @@
 pragma solidity 0.6.4;
 
-import "./interface/ISystemReward.sol";
-import "./interface/IRelayerHub.sol";
-import "./interface/ILightClient.sol";
+import "./interface/0.6.x/ISystemReward.sol";
+import "./interface/0.6.x/IRelayerHub.sol";
+import "./interface/0.6.x/ILightClient.sol";
 
 contract System {
     bool public alreadyInit;
diff --git a/contracts/SystemReward.sol b/contracts/SystemReward.sol
index 0998b0f4..fa5ad587 100644
--- a/contracts/SystemReward.sol
+++ b/contracts/SystemReward.sol
@@ -1,9 +1,9 @@
 pragma solidity 0.6.4;
 
 import "./System.sol";
-import "./lib/Memory.sol";
-import "./interface/IParamSubscriber.sol";
-import "./interface/ISystemReward.sol";
+import "./lib/0.6.x/Memory.sol";
+import "./interface/0.6.x/IParamSubscriber.sol";
+import "./interface/0.6.x/ISystemReward.sol";
 
 contract SystemReward is System, IParamSubscriber, ISystemReward {
     uint256 public constant MAX_REWARDS = 5e18;
diff --git a/contracts/BC_fusion/System.sol b/contracts/SystemV2.sol
similarity index 99%
rename from contracts/BC_fusion/System.sol
rename to contracts/SystemV2.sol
index b08e2c81..d7520425 100644
--- a/contracts/BC_fusion/System.sol
+++ b/contracts/SystemV2.sol
@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: GPL-3.0-or-later
 pragma solidity 0.8.17;
 
-contract System {
+contract SystemV2 {
     /*----------------- constants -----------------*/
     uint8 public constant STAKING_CHANNELID = 0x08;
     uint8 public constant BC_FUSION_CHANNELID = 0x11; // new channel id for cross-chain redelegate from Beacon Chain to Smart Chain after Feynman upgrade
diff --git a/contracts/TokenHub.sol b/contracts/TokenHub.sol
index fc2902b9..79db085f 100644
--- a/contracts/TokenHub.sol
+++ b/contracts/TokenHub.sol
@@ -1,16 +1,16 @@
 pragma solidity 0.6.4;
 
-import "./interface/IBEP20.sol";
-import "./interface/ITokenHub.sol";
-import "./interface/IParamSubscriber.sol";
-import "./interface/IApplication.sol";
-import "./interface/ICrossChain.sol";
-import "./interface/ISystemReward.sol";
-import "./lib/SafeMath.sol";
-import "./lib/RLPEncode.sol";
-import "./lib/RLPDecode.sol";
-import "./lib/BytesToTypes.sol";
-import "./lib/Memory.sol";
+import "./interface/0.6.x/IBEP20.sol";
+import "./interface/0.6.x/ITokenHub.sol";
+import "./interface/0.6.x/IParamSubscriber.sol";
+import "./interface/0.6.x/IApplication.sol";
+import "./interface/0.6.x/ICrossChain.sol";
+import "./interface/0.6.x/ISystemReward.sol";
+import "./lib/0.6.x/SafeMath.sol";
+import "./lib/0.6.x/RLPEncode.sol";
+import "./lib/0.6.x/RLPDecode.sol";
+import "./lib/0.6.x/BytesToTypes.sol";
+import "./lib/0.6.x/Memory.sol";
 import "./System.sol";
 
 contract TokenHub is ITokenHub, System, IParamSubscriber, IApplication, ISystemReward {
diff --git a/contracts/BC_fusion/TokenRecoverPortal.sol b/contracts/TokenRecoverPortal.sol
similarity index 97%
rename from contracts/BC_fusion/TokenRecoverPortal.sol
rename to contracts/TokenRecoverPortal.sol
index 44186cf4..0ca51e75 100644
--- a/contracts/BC_fusion/TokenRecoverPortal.sol
+++ b/contracts/TokenRecoverPortal.sol
@@ -5,11 +5,11 @@ import "@openzeppelin/contracts-upgradeable/security/ReentrancyGuardUpgradeable.
 import "@openzeppelin/contracts/utils/cryptography/MerkleProof.sol";
 import "@openzeppelin/contracts/utils/cryptography/ECDSA.sol";
 
-import "./System.sol";
+import "./SystemV2.sol";
 import "./extension/Protectable.sol";
-import "./interface/ITokenHub.sol";
-import "./interface/ITokenRecoverPortal.sol";
-import "./lib/Utils.sol";
+import "./interface/0.8.x/ITokenHub.sol";
+import "./interface/0.8.x/ITokenRecoverPortal.sol";
+import "./lib/0.8.x/Utils.sol";
 
 /**
  * @title TokenRecoverPortal is used to recover the token from BC users.
@@ -18,7 +18,7 @@ import "./lib/Utils.sol";
  * The BC users can recover the token from TokenHub after the merkle tree root is generated.
  * For more details, please refer to the BEP-299(https://github.com/bnb-chain/BEPs/pull/299).
  */
-contract TokenRecoverPortal is System, Initializable, ReentrancyGuardUpgradeable, Protectable {
+contract TokenRecoverPortal is SystemV2, Initializable, ReentrancyGuardUpgradeable, Protectable {
     using Utils for string;
     using Utils for bytes;
 
diff --git a/contracts/bep20_template/BEP20Token.template b/contracts/bep20_template/BEP20Token.template
deleted file mode 100644
index 4a8a2b86..00000000
--- a/contracts/bep20_template/BEP20Token.template
+++ /dev/null
@@ -1,593 +0,0 @@
-// SPDX-License-Identifier: MIT
-pragma solidity >0.4.0 <= 0.9.0;
-
-interface IBEP20 {
-  /**
-   * @dev Returns the amount of tokens in existence.
-   */
-  function totalSupply() external view returns (uint256);
-
-  /**
-   * @dev Returns the token decimals.
-   */
-  function decimals() external view returns (uint8);
-
-  /**
-   * @dev Returns the token symbol.
-   */
-  function symbol() external view returns (string memory);
-
-  /**
-  * @dev Returns the token name.
-  */
-  function name() external view returns (string memory);
-
-  /**
-   * @dev Returns the bep token owner.
-   */
-  function getOwner() external view returns (address);
-
-  /**
-   * @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 `recipient`.
-   *
-   * Returns a boolean value indicating whether the operation succeeded.
-   *
-   * Emits a {Transfer} event.
-   */
-  function transfer(address recipient, 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 `sender` to `recipient` 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 sender, address recipient, uint256 amount) external returns (bool);
-
-  /**
-   * @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 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 GSN 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.
- */
-contract Context {
-  // Empty internal constructor, to prevent people from mistakenly deploying
-  // an instance of this contract, which should be used via inheritance.
-  constructor () { }
-
-  function _msgSender() internal view returns (address) {
-    return msg.sender;
-  }
-
-  function _msgData() internal view returns (bytes memory) {
-    this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
-    return msg.data;
-  }
-}
-
-/**
- * @dev Wrappers over Solidity's arithmetic operations with added overflow
- * checks.
- *
- * Arithmetic operations in Solidity wrap on overflow. This can easily result
- * in bugs, because programmers usually assume that an overflow raises an
- * error, which is the standard behavior in high level programming languages.
- * `SafeMath` restores this intuition by reverting the transaction when an
- * operation overflows.
- *
- * Using this library instead of the unchecked operations eliminates an entire
- * class of bugs, so it's recommended to use it always.
- */
-library SafeMath {
-  /**
-   * @dev Returns the addition of two unsigned integers, reverting on
-   * overflow.
-   *
-   * Counterpart to Solidity's `+` operator.
-   *
-   * Requirements:
-   * - Addition cannot overflow.
-   */
-  function add(uint256 a, uint256 b) internal pure returns (uint256) {
-    uint256 c = a + b;
-    require(c >= a, "SafeMath: addition overflow");
-
-    return c;
-  }
-
-  /**
-   * @dev Returns the subtraction of two unsigned integers, reverting on
-   * overflow (when the result is negative).
-   *
-   * Counterpart to Solidity's `-` operator.
-   *
-   * Requirements:
-   * - Subtraction cannot overflow.
-   */
-  function sub(uint256 a, uint256 b) internal pure returns (uint256) {
-    return sub(a, b, "SafeMath: subtraction overflow");
-  }
-
-  /**
-   * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
-   * overflow (when the result is negative).
-   *
-   * Counterpart to Solidity's `-` operator.
-   *
-   * Requirements:
-   * - Subtraction cannot overflow.
-   */
-  function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
-    require(b <= a, errorMessage);
-    uint256 c = a - b;
-
-    return c;
-  }
-
-  /**
-   * @dev Returns the multiplication of two unsigned integers, reverting on
-   * overflow.
-   *
-   * Counterpart to Solidity's `*` operator.
-   *
-   * Requirements:
-   * - Multiplication cannot overflow.
-   */
-  function mul(uint256 a, uint256 b) internal pure returns (uint256) {
-    // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
-    // benefit is lost if 'b' is also tested.
-    // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
-    if (a == 0) {
-      return 0;
-    }
-
-    uint256 c = a * b;
-    require(c / a == b, "SafeMath: multiplication overflow");
-
-    return c;
-  }
-
-  /**
-   * @dev Returns the integer division of two unsigned integers. Reverts on
-   * division by zero. The result is rounded towards zero.
-   *
-   * Counterpart to Solidity's `/` operator. Note: this function uses a
-   * `revert` opcode (which leaves remaining gas untouched) while Solidity
-   * uses an invalid opcode to revert (consuming all remaining gas).
-   *
-   * Requirements:
-   * - The divisor cannot be zero.
-   */
-  function div(uint256 a, uint256 b) internal pure returns (uint256) {
-    return div(a, b, "SafeMath: division by zero");
-  }
-
-  /**
-   * @dev Returns the integer division of two unsigned integers. Reverts with custom message on
-   * division by zero. The result is rounded towards zero.
-   *
-   * Counterpart to Solidity's `/` operator. Note: this function uses a
-   * `revert` opcode (which leaves remaining gas untouched) while Solidity
-   * uses an invalid opcode to revert (consuming all remaining gas).
-   *
-   * Requirements:
-   * - The divisor cannot be zero.
-   */
-  function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
-    // Solidity only automatically asserts when dividing by 0
-    require(b > 0, errorMessage);
-    uint256 c = a / b;
-    // assert(a == b * c + a % b); // There is no case in which this doesn't hold
-
-    return c;
-  }
-
-  /**
-   * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
-   * Reverts when dividing by zero.
-   *
-   * Counterpart to Solidity's `%` operator. This function uses a `revert`
-   * opcode (which leaves remaining gas untouched) while Solidity uses an
-   * invalid opcode to revert (consuming all remaining gas).
-   *
-   * Requirements:
-   * - The divisor cannot be zero.
-   */
-  function mod(uint256 a, uint256 b) internal pure returns (uint256) {
-    return mod(a, b, "SafeMath: modulo by zero");
-  }
-
-  /**
-   * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
-   * Reverts with custom message when dividing by zero.
-   *
-   * Counterpart to Solidity's `%` operator. This function uses a `revert`
-   * opcode (which leaves remaining gas untouched) while Solidity uses an
-   * invalid opcode to revert (consuming all remaining gas).
-   *
-   * Requirements:
-   * - The divisor cannot be zero.
-   */
-  function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
-    require(b != 0, errorMessage);
-    return a % b;
-  }
-}
-
-/**
- * @dev Contract module which provides a basic access control mechanism, where
- * there is an account (an owner) that can be granted exclusive access to
- * specific functions.
- *
- * By default, the owner account will be the one that deploys the contract. This
- * can later be changed with {transferOwnership}.
- *
- * This module is used through inheritance. It will make available the modifier
- * `onlyOwner`, which can be applied to your functions to restrict their use to
- * the owner.
- */
-contract Ownable is Context {
-  address private _owner;
-
-  event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
-
-  /**
-   * @dev Initializes the contract setting the deployer as the initial owner.
-   */
-  constructor ()  {
-    address msgSender = _msgSender();
-    _owner = msgSender;
-    emit OwnershipTransferred(address(0), msgSender);
-  }
-
-  /**
-   * @dev Returns the address of the current owner.
-   */
-  function owner() public view returns (address) {
-    return _owner;
-  }
-
-  /**
-   * @dev Throws if called by any account other than the owner.
-   */
-  modifier onlyOwner() {
-    require(_owner == _msgSender(), "Ownable: caller is not the owner");
-    _;
-  }
-
-  /**
-   * @dev Leaves the contract without owner. It will not be possible to call
-   * `onlyOwner` functions anymore. Can only be called by the current owner.
-   *
-   * NOTE: Renouncing ownership will leave the contract without an owner,
-   * thereby removing any functionality that is only available to the owner.
-   */
-  function renounceOwnership() public onlyOwner {
-    emit OwnershipTransferred(_owner, address(0));
-    _owner = address(0);
-  }
-
-  /**
-   * @dev Transfers ownership of the contract to a new account (`newOwner`).
-   * Can only be called by the current owner.
-   */
-  function transferOwnership(address newOwner) public onlyOwner {
-    _transferOwnership(newOwner);
-  }
-
-  /**
-   * @dev Transfers ownership of the contract to a new account (`newOwner`).
-   */
-  function _transferOwnership(address newOwner) internal {
-    require(newOwner != address(0), "Ownable: new owner is the zero address");
-    emit OwnershipTransferred(_owner, newOwner);
-    _owner = newOwner;
-  }
-}
-
-contract BEP20Token is Context, IBEP20, Ownable {
-  using SafeMath for uint256;
-
-  mapping (address => uint256) private _balances;
-
-  mapping (address => mapping (address => uint256)) private _allowances;
-
-  uint256 private _totalSupply;
-  uint8 private _decimals;
-  string private _symbol;
-  string private _name;
-
-  constructor() public {
-    _name = "ABCToken";
-    _symbol = "ABC";
-    _decimals = 18;
-    _totalSupply = 1000000000000000;
-    _balances[msg.sender] = _totalSupply;
-
-    emit Transfer(address(0), msg.sender, _totalSupply);
-  }
-
-  /**
-   * @dev Returns the bep token owner.
-   */
-  function getOwner() external view returns (address) {
-    return owner();
-  }
-
-  /**
-   * @dev Returns the token decimals.
-   */
-  function decimals() external view returns (uint8) {
-    return _decimals;
-  }
-
-  /**
-   * @dev Returns the token symbol.
-   */
-  function symbol() external view returns (string memory) {
-    return _symbol;
-  }
-
-  /**
-  * @dev Returns the token name.
-  */
-  function name() external view returns (string memory) {
-    return _name;
-  }
-
-  /**
-   * @dev See {BEP20-totalSupply}.
-   */
-  function totalSupply() external view returns (uint256) {
-    return _totalSupply;
-  }
-
-  /**
-   * @dev See {BEP20-balanceOf}.
-   */
-  function balanceOf(address account) external view returns (uint256) {
-    return _balances[account];
-  }
-
-  /**
-   * @dev See {BEP20-transfer}.
-   *
-   * Requirements:
-   *
-   * - `recipient` cannot be the zero address.
-   * - the caller must have a balance of at least `amount`.
-   */
-  function transfer(address recipient, uint256 amount) external returns (bool) {
-    _transfer(_msgSender(), recipient, amount);
-    return true;
-  }
-
-  /**
-   * @dev See {BEP20-allowance}.
-   */
-  function allowance(address owner, address spender) external view returns (uint256) {
-    return _allowances[owner][spender];
-  }
-
-  /**
-   * @dev See {BEP20-approve}.
-   *
-   * Requirements:
-   *
-   * - `spender` cannot be the zero address.
-   */
-  function approve(address spender, uint256 amount) external returns (bool) {
-    _approve(_msgSender(), spender, amount);
-    return true;
-  }
-
-  /**
-   * @dev See {BEP20-transferFrom}.
-   *
-   * Emits an {Approval} event indicating the updated allowance. This is not
-   * required by the EIP. See the note at the beginning of {BEP20};
-   *
-   * Requirements:
-   * - `sender` and `recipient` cannot be the zero address.
-   * - `sender` must have a balance of at least `amount`.
-   * - the caller must have allowance for `sender`'s tokens of at least
-   * `amount`.
-   */
-  function transferFrom(address sender, address recipient, uint256 amount) external returns (bool) {
-    _transfer(sender, recipient, amount);
-    _approve(sender, _msgSender(), _allowances[sender][_msgSender()].sub(amount, "BEP20: transfer amount exceeds allowance"));
-    return true;
-  }
-
-  /**
-   * @dev Atomically increases the allowance granted to `spender` by the caller.
-   *
-   * This is an alternative to {approve} that can be used as a mitigation for
-   * problems described in {BEP20-approve}.
-   *
-   * Emits an {Approval} event indicating the updated allowance.
-   *
-   * Requirements:
-   *
-   * - `spender` cannot be the zero address.
-   */
-  function increaseAllowance(address spender, uint256 addedValue) public returns (bool) {
-    _approve(_msgSender(), spender, _allowances[_msgSender()][spender].add(addedValue));
-    return true;
-  }
-
-  /**
-   * @dev Atomically decreases the allowance granted to `spender` by the caller.
-   *
-   * This is an alternative to {approve} that can be used as a mitigation for
-   * problems described in {BEP20-approve}.
-   *
-   * Emits an {Approval} event indicating the updated allowance.
-   *
-   * Requirements:
-   *
-   * - `spender` cannot be the zero address.
-   * - `spender` must have allowance for the caller of at least
-   * `subtractedValue`.
-   */
-  function decreaseAllowance(address spender, uint256 subtractedValue) public returns (bool) {
-    _approve(_msgSender(), spender, _allowances[_msgSender()][spender].sub(subtractedValue, "BEP20: decreased allowance below zero"));
-    return true;
-  }
-
-  /**
-   * @dev Creates `amount` tokens and assigns them to `msg.sender`, increasing
-   * the total supply.
-   *
-   * Requirements
-   *
-   * - `msg.sender` must be the token owner
-   */
-  function mint(uint256 amount) public onlyOwner returns (bool) {
-    _mint(_msgSender(), amount);
-    return true;
-  }
-
-  /**
-   * @dev Moves tokens `amount` from `sender` to `recipient`.
-   *
-   * This is internal function is equivalent to {transfer}, and can be used to
-   * e.g. implement automatic token fees, slashing mechanisms, etc.
-   *
-   * Emits a {Transfer} event.
-   *
-   * Requirements:
-   *
-   * - `sender` cannot be the zero address.
-   * - `recipient` cannot be the zero address.
-   * - `sender` must have a balance of at least `amount`.
-   */
-  function _transfer(address sender, address recipient, uint256 amount) internal {
-    require(sender != address(0), "BEP20: transfer from the zero address");
-    require(recipient != address(0), "BEP20: transfer to the zero address");
-
-    _balances[sender] = _balances[sender].sub(amount, "BEP20: transfer amount exceeds balance");
-    _balances[recipient] = _balances[recipient].add(amount);
-    emit Transfer(sender, recipient, amount);
-  }
-
-  /** @dev Creates `amount` tokens and assigns them to `account`, increasing
-   * the total supply.
-   *
-   * Emits a {Transfer} event with `from` set to the zero address.
-   *
-   * Requirements
-   *
-   * - `to` cannot be the zero address.
-   */
-  function _mint(address account, uint256 amount) internal {
-    require(account != address(0), "BEP20: mint to the zero address");
-
-    _totalSupply = _totalSupply.add(amount);
-    _balances[account] = _balances[account].add(amount);
-    emit Transfer(address(0), account, amount);
-  }
-
-  /**
-   * @dev Destroys `amount` tokens from `account`, reducing the
-   * total supply.
-   *
-   * Emits a {Transfer} event with `to` set to the zero address.
-   *
-   * Requirements
-   *
-   * - `account` cannot be the zero address.
-   * - `account` must have at least `amount` tokens.
-   */
-  function _burn(address account, uint256 amount) internal {
-    require(account != address(0), "BEP20: burn from the zero address");
-
-    _balances[account] = _balances[account].sub(amount, "BEP20: burn amount exceeds balance");
-    _totalSupply = _totalSupply.sub(amount);
-    emit Transfer(account, address(0), amount);
-  }
-
-  /**
-   * @dev Sets `amount` as the allowance of `spender` over the `owner`s tokens.
-   *
-   * This is internal function is equivalent to `approve`, and can be used to
-   * e.g. set automatic allowances for certain subsystems, etc.
-   *
-   * Emits an {Approval} event.
-   *
-   * Requirements:
-   *
-   * - `owner` cannot be the zero address.
-   * - `spender` cannot be the zero address.
-   */
-  function _approve(address owner, address spender, uint256 amount) internal {
-    require(owner != address(0), "BEP20: approve from the zero address");
-    require(spender != address(0), "BEP20: approve to the zero address");
-
-    _allowances[owner][spender] = amount;
-    emit Approval(owner, spender, amount);
-  }
-
-  /**
-   * @dev Destroys `amount` tokens from `account`.`amount` is then deducted
-   * from the caller's allowance.
-   *
-   * See {_burn} and {_approve}.
-   */
-  function _burnFrom(address account, uint256 amount) internal {
-    _burn(account, amount);
-    _approve(account, _msgSender(), _allowances[account][_msgSender()].sub(amount, "BEP20: burn amount exceeds allowance"));
-  }
-}
diff --git a/contracts/CrossChain.sol b/contracts/deprecated/CrossChain.sol
similarity index 97%
rename from contracts/CrossChain.sol
rename to contracts/deprecated/CrossChain.sol
index a40d7f8e..2bbd0200 100644
--- a/contracts/CrossChain.sol
+++ b/contracts/deprecated/CrossChain.sol
@@ -1,17 +1,17 @@
 pragma solidity 0.6.4;
 
-import "./interface/IApplication.sol";
-import "./interface/ICrossChain.sol";
-import "./interface/ITokenHub.sol";
-import "./interface/ILightClient.sol";
-import "./interface/IRelayerIncentivize.sol";
-import "./interface/IRelayerHub.sol";
-import "./interface/IBSCValidatorSetV2.sol";
-import "./lib/Memory.sol";
-import "./lib/BytesToTypes.sol";
-import "./interface/IParamSubscriber.sol";
-import "./System.sol";
-import "./MerkleProof.sol";
+import "../interface/0.6.x/IApplication.sol";
+import "../interface/0.6.x/ICrossChain.sol";
+import "../interface/0.6.x/ITokenHub.sol";
+import "../interface/0.6.x/ILightClient.sol";
+import "../interface/0.6.x/IRelayerIncentivize.sol";
+import "../interface/0.6.x/IRelayerHub.sol";
+import "../interface/0.6.x/IBSCValidatorSetV2.sol";
+import "../lib/0.6.x/Memory.sol";
+import "../lib/0.6.x/BytesToTypes.sol";
+import "../interface/0.6.x/IParamSubscriber.sol";
+import "../System.sol";
+import "../lib/0.6.x/MerkleProof.sol";
 
 contract CrossChain is System, ICrossChain, IParamSubscriber {
     // constant variables
diff --git a/contracts/RelayerHub.sol b/contracts/deprecated/RelayerHub.sol
similarity index 96%
rename from contracts/RelayerHub.sol
rename to contracts/deprecated/RelayerHub.sol
index b9b1bcfd..a907fbd2 100644
--- a/contracts/RelayerHub.sol
+++ b/contracts/deprecated/RelayerHub.sol
@@ -1,11 +1,11 @@
 pragma solidity 0.6.4;
 
-import "./lib/BytesToTypes.sol";
-import "./lib/Memory.sol";
-import "./interface/IRelayerHub.sol";
-import "./interface/IParamSubscriber.sol";
-import "./System.sol";
-import "./lib/SafeMath.sol";
+import "../lib/0.6.x/BytesToTypes.sol";
+import "../lib/0.6.x/Memory.sol";
+import "../interface/0.6.x/IRelayerHub.sol";
+import "../interface/0.6.x/IParamSubscriber.sol";
+import "../System.sol";
+import "../lib/0.6.x/SafeMath.sol";
 
 contract RelayerHub is IRelayerHub, System, IParamSubscriber {
     using SafeMath for uint256;
diff --git a/contracts/RelayerIncentivize.sol b/contracts/deprecated/RelayerIncentivize.sol
similarity index 97%
rename from contracts/RelayerIncentivize.sol
rename to contracts/deprecated/RelayerIncentivize.sol
index 16f2e5db..22ba9591 100644
--- a/contracts/RelayerIncentivize.sol
+++ b/contracts/deprecated/RelayerIncentivize.sol
@@ -1,12 +1,12 @@
 pragma solidity 0.6.4;
 
-import "./interface/IRelayerIncentivize.sol";
-import "./System.sol";
-import "./lib/SafeMath.sol";
-import "./lib/Memory.sol";
-import "./lib/BytesToTypes.sol";
-import "./interface/IParamSubscriber.sol";
-import "./interface/ISystemReward.sol";
+import "../interface/0.6.x/IRelayerIncentivize.sol";
+import "../System.sol";
+import "../lib/0.6.x/SafeMath.sol";
+import "../lib/0.6.x/Memory.sol";
+import "../lib/0.6.x/BytesToTypes.sol";
+import "../interface/0.6.x/IParamSubscriber.sol";
+import "../interface/0.6.x/ISystemReward.sol";
 
 contract RelayerIncentivize is IRelayerIncentivize, System, IParamSubscriber {
     using SafeMath for uint256;
diff --git a/contracts/Staking.sol b/contracts/deprecated/Staking.sol
similarity index 98%
rename from contracts/Staking.sol
rename to contracts/deprecated/Staking.sol
index 208b7ab3..b099f7ea 100644
--- a/contracts/Staking.sol
+++ b/contracts/deprecated/Staking.sol
@@ -1,18 +1,18 @@
 pragma solidity 0.6.4;
 
-import "./System.sol";
-import "./interface/IApplication.sol";
-import "./interface/ICrossChain.sol";
-import "./interface/IParamSubscriber.sol";
-import "./interface/IStaking.sol";
-import "./interface/ITokenHub.sol";
-import "./lib/BytesToTypes.sol";
-import "./lib/BytesLib.sol";
-import "./lib/CmnPkg.sol";
-import "./lib/Memory.sol";
-import "./lib/RLPEncode.sol";
-import "./lib/RLPDecode.sol";
-import "./lib/SafeMath.sol";
+import "../System.sol";
+import "../interface/0.6.x/IApplication.sol";
+import "../interface/0.6.x/ICrossChain.sol";
+import "../interface/0.6.x/IParamSubscriber.sol";
+import "../interface/0.6.x/IStaking.sol";
+import "../interface/0.6.x/ITokenHub.sol";
+import "../lib/0.6.x/BytesToTypes.sol";
+import "../lib/0.6.x/BytesLib.sol";
+import "../lib/0.6.x/CmnPkg.sol";
+import "../lib/0.6.x/Memory.sol";
+import "../lib/0.6.x/RLPEncode.sol";
+import "../lib/0.6.x/RLPDecode.sol";
+import "../lib/0.6.x/SafeMath.sol";
 
 contract Staking is IStaking, System, IParamSubscriber, IApplication {
     using SafeMath for uint256;
diff --git a/contracts/TendermintLightClient.sol b/contracts/deprecated/TendermintLightClient.sol
similarity index 97%
rename from contracts/TendermintLightClient.sol
rename to contracts/deprecated/TendermintLightClient.sol
index e0a1e01e..ad971bdf 100644
--- a/contracts/TendermintLightClient.sol
+++ b/contracts/deprecated/TendermintLightClient.sol
@@ -1,11 +1,11 @@
 pragma solidity 0.6.4;
 
-import "./lib/Memory.sol";
-import "./lib/BytesToTypes.sol";
-import "./interface/ILightClient.sol";
-import "./interface/ISystemReward.sol";
-import "./interface/IParamSubscriber.sol";
-import "./System.sol";
+import "../lib/0.6.x/Memory.sol";
+import "../lib/0.6.x/BytesToTypes.sol";
+import "../interface/0.6.x/ILightClient.sol";
+import "../interface/0.6.x/ISystemReward.sol";
+import "../interface/0.6.x/IParamSubscriber.sol";
+import "../System.sol";
 
 contract TendermintLightClient is ILightClient, System, IParamSubscriber {
     struct ConsensusState {
diff --git a/contracts/TokenManager.sol b/contracts/deprecated/TokenManager.sol
similarity index 98%
rename from contracts/TokenManager.sol
rename to contracts/deprecated/TokenManager.sol
index f5f8ca78..4e06cdde 100644
--- a/contracts/TokenManager.sol
+++ b/contracts/deprecated/TokenManager.sol
@@ -1,14 +1,14 @@
 pragma solidity 0.6.4;
 
-import "./interface/IBEP20.sol";
-import "./interface/ITokenHub.sol";
-import "./interface/IApplication.sol";
-import "./interface/ICrossChain.sol";
-import "./interface/IParamSubscriber.sol";
-import "./lib/SafeMath.sol";
-import "./lib/RLPEncode.sol";
-import "./lib/RLPDecode.sol";
-import "./System.sol";
+import "../interface/0.6.x/IBEP20.sol";
+import "../interface/0.6.x/ITokenHub.sol";
+import "../interface/0.6.x/IApplication.sol";
+import "../interface/0.6.x/ICrossChain.sol";
+import "../interface/0.6.x/IParamSubscriber.sol";
+import "../lib/0.6.x/SafeMath.sol";
+import "../lib/0.6.x/RLPEncode.sol";
+import "../lib/0.6.x/RLPDecode.sol";
+import "../System.sol";
 
 contract TokenManager is System, IApplication, IParamSubscriber {
     using SafeMath for uint256;
diff --git a/contracts/tool/BSCValidatorSetTool.sol b/contracts/extension/BSCValidatorSetTool.sol
similarity index 98%
rename from contracts/tool/BSCValidatorSetTool.sol
rename to contracts/extension/BSCValidatorSetTool.sol
index 12173b85..9341ee9d 100644
--- a/contracts/tool/BSCValidatorSetTool.sol
+++ b/contracts/extension/BSCValidatorSetTool.sol
@@ -1,7 +1,7 @@
 pragma solidity 0.6.4;
 
-import "../lib/RLPDecode.sol";
-import "../lib/Memory.sol";
+import "../lib/0.6.x/RLPDecode.sol";
+import "../lib/0.6.x/Memory.sol";
 
 contract BSCValidatorSetTool {
     bytes public constant INIT_VALIDATORSET_BYTES =
diff --git a/contracts/BC_fusion/extension/Protectable.sol b/contracts/extension/Protectable.sol
similarity index 100%
rename from contracts/BC_fusion/extension/Protectable.sol
rename to contracts/extension/Protectable.sol
diff --git a/contracts/interface/IApplication.sol b/contracts/interface/0.6.x/IApplication.sol
similarity index 100%
rename from contracts/interface/IApplication.sol
rename to contracts/interface/0.6.x/IApplication.sol
diff --git a/contracts/interface/IBEP20.sol b/contracts/interface/0.6.x/IBEP20.sol
similarity index 100%
rename from contracts/interface/IBEP20.sol
rename to contracts/interface/0.6.x/IBEP20.sol
diff --git a/contracts/interface/IBSCValidatorSet.sol b/contracts/interface/0.6.x/IBSCValidatorSet.sol
similarity index 100%
rename from contracts/interface/IBSCValidatorSet.sol
rename to contracts/interface/0.6.x/IBSCValidatorSet.sol
diff --git a/contracts/interface/IBSCValidatorSetV2.sol b/contracts/interface/0.6.x/IBSCValidatorSetV2.sol
similarity index 100%
rename from contracts/interface/IBSCValidatorSetV2.sol
rename to contracts/interface/0.6.x/IBSCValidatorSetV2.sol
diff --git a/contracts/interface/ICrossChain.sol b/contracts/interface/0.6.x/ICrossChain.sol
similarity index 100%
rename from contracts/interface/ICrossChain.sol
rename to contracts/interface/0.6.x/ICrossChain.sol
diff --git a/contracts/interface/ILightClient.sol b/contracts/interface/0.6.x/ILightClient.sol
similarity index 100%
rename from contracts/interface/ILightClient.sol
rename to contracts/interface/0.6.x/ILightClient.sol
diff --git a/contracts/interface/IParamSubscriber.sol b/contracts/interface/0.6.x/IParamSubscriber.sol
similarity index 100%
rename from contracts/interface/IParamSubscriber.sol
rename to contracts/interface/0.6.x/IParamSubscriber.sol
diff --git a/contracts/interface/IRelayerHub.sol b/contracts/interface/0.6.x/IRelayerHub.sol
similarity index 100%
rename from contracts/interface/IRelayerHub.sol
rename to contracts/interface/0.6.x/IRelayerHub.sol
diff --git a/contracts/interface/IRelayerIncentivize.sol b/contracts/interface/0.6.x/IRelayerIncentivize.sol
similarity index 100%
rename from contracts/interface/IRelayerIncentivize.sol
rename to contracts/interface/0.6.x/IRelayerIncentivize.sol
diff --git a/contracts/interface/ISlashIndicator.sol b/contracts/interface/0.6.x/ISlashIndicator.sol
similarity index 100%
rename from contracts/interface/ISlashIndicator.sol
rename to contracts/interface/0.6.x/ISlashIndicator.sol
diff --git a/contracts/interface/IStakeHub.sol b/contracts/interface/0.6.x/IStakeHub.sol
similarity index 100%
rename from contracts/interface/IStakeHub.sol
rename to contracts/interface/0.6.x/IStakeHub.sol
diff --git a/contracts/interface/IStaking.sol b/contracts/interface/0.6.x/IStaking.sol
similarity index 100%
rename from contracts/interface/IStaking.sol
rename to contracts/interface/0.6.x/IStaking.sol
diff --git a/contracts/interface/ISystemReward.sol b/contracts/interface/0.6.x/ISystemReward.sol
similarity index 100%
rename from contracts/interface/ISystemReward.sol
rename to contracts/interface/0.6.x/ISystemReward.sol
diff --git a/contracts/interface/ITokenHub.sol b/contracts/interface/0.6.x/ITokenHub.sol
similarity index 100%
rename from contracts/interface/ITokenHub.sol
rename to contracts/interface/0.6.x/ITokenHub.sol
diff --git a/contracts/BC_fusion/interface/IBSCValidatorSet.sol b/contracts/interface/0.8.x/IBSCValidatorSet.sol
similarity index 100%
rename from contracts/BC_fusion/interface/IBSCValidatorSet.sol
rename to contracts/interface/0.8.x/IBSCValidatorSet.sol
diff --git a/contracts/BC_fusion/interface/ICrossChain.sol b/contracts/interface/0.8.x/ICrossChain.sol
similarity index 100%
rename from contracts/BC_fusion/interface/ICrossChain.sol
rename to contracts/interface/0.8.x/ICrossChain.sol
diff --git a/contracts/BC_fusion/interface/IGovToken.sol b/contracts/interface/0.8.x/IGovToken.sol
similarity index 100%
rename from contracts/BC_fusion/interface/IGovToken.sol
rename to contracts/interface/0.8.x/IGovToken.sol
diff --git a/contracts/BC_fusion/interface/IStakeCredit.sol b/contracts/interface/0.8.x/IStakeCredit.sol
similarity index 100%
rename from contracts/BC_fusion/interface/IStakeCredit.sol
rename to contracts/interface/0.8.x/IStakeCredit.sol
diff --git a/contracts/BC_fusion/interface/IStakeHub.sol b/contracts/interface/0.8.x/IStakeHub.sol
similarity index 100%
rename from contracts/BC_fusion/interface/IStakeHub.sol
rename to contracts/interface/0.8.x/IStakeHub.sol
diff --git a/contracts/BC_fusion/interface/ITokenHub.sol b/contracts/interface/0.8.x/ITokenHub.sol
similarity index 100%
rename from contracts/BC_fusion/interface/ITokenHub.sol
rename to contracts/interface/0.8.x/ITokenHub.sol
diff --git a/contracts/BC_fusion/interface/ITokenRecoverPortal.sol b/contracts/interface/0.8.x/ITokenRecoverPortal.sol
similarity index 100%
rename from contracts/BC_fusion/interface/ITokenRecoverPortal.sol
rename to contracts/interface/0.8.x/ITokenRecoverPortal.sol
diff --git a/contracts/lib/BytesLib.sol b/contracts/lib/0.6.x/BytesLib.sol
similarity index 100%
rename from contracts/lib/BytesLib.sol
rename to contracts/lib/0.6.x/BytesLib.sol
diff --git a/contracts/lib/BytesToTypes.sol b/contracts/lib/0.6.x/BytesToTypes.sol
similarity index 100%
rename from contracts/lib/BytesToTypes.sol
rename to contracts/lib/0.6.x/BytesToTypes.sol
diff --git a/contracts/lib/CmnPkg.sol b/contracts/lib/0.6.x/CmnPkg.sol
similarity index 100%
rename from contracts/lib/CmnPkg.sol
rename to contracts/lib/0.6.x/CmnPkg.sol
diff --git a/contracts/bep20_template/LICENCE b/contracts/lib/0.6.x/LICENCE
similarity index 100%
rename from contracts/bep20_template/LICENCE
rename to contracts/lib/0.6.x/LICENCE
diff --git a/contracts/lib/Memory.sol b/contracts/lib/0.6.x/Memory.sol
similarity index 100%
rename from contracts/lib/Memory.sol
rename to contracts/lib/0.6.x/Memory.sol
diff --git a/contracts/MerkleProof.sol b/contracts/lib/0.6.x/MerkleProof.sol
similarity index 98%
rename from contracts/MerkleProof.sol
rename to contracts/lib/0.6.x/MerkleProof.sol
index 51bdd209..72a107f3 100644
--- a/contracts/MerkleProof.sol
+++ b/contracts/lib/0.6.x/MerkleProof.sol
@@ -1,6 +1,6 @@
 pragma solidity 0.6.4;
 
-import "./lib/Memory.sol";
+import "./Memory.sol";
 
 library MerkleProof {
     function validateMerkleProof(
diff --git a/contracts/lib/RLPDecode.sol b/contracts/lib/0.6.x/RLPDecode.sol
similarity index 100%
rename from contracts/lib/RLPDecode.sol
rename to contracts/lib/0.6.x/RLPDecode.sol
diff --git a/contracts/lib/RLPEncode.sol b/contracts/lib/0.6.x/RLPEncode.sol
similarity index 100%
rename from contracts/lib/RLPEncode.sol
rename to contracts/lib/0.6.x/RLPEncode.sol
diff --git a/contracts/lib/SafeMath.sol b/contracts/lib/0.6.x/SafeMath.sol
similarity index 100%
rename from contracts/lib/SafeMath.sol
rename to contracts/lib/0.6.x/SafeMath.sol
diff --git a/contracts/lib/SizeOf.sol b/contracts/lib/0.6.x/SizeOf.sol
similarity index 100%
rename from contracts/lib/SizeOf.sol
rename to contracts/lib/0.6.x/SizeOf.sol
diff --git a/contracts/lib/TypesToBytes.sol b/contracts/lib/0.6.x/TypesToBytes.sol
similarity index 100%
rename from contracts/lib/TypesToBytes.sol
rename to contracts/lib/0.6.x/TypesToBytes.sol
diff --git a/contracts/BC_fusion/lib/RLPDecode.sol b/contracts/lib/0.8.x/RLPDecode.sol
similarity index 100%
rename from contracts/BC_fusion/lib/RLPDecode.sol
rename to contracts/lib/0.8.x/RLPDecode.sol
diff --git a/contracts/BC_fusion/lib/Utils.sol b/contracts/lib/0.8.x/Utils.sol
similarity index 100%
rename from contracts/BC_fusion/lib/Utils.sol
rename to contracts/lib/0.8.x/Utils.sol
diff --git a/contracts/lib/LICENCE b/contracts/lib/LICENCE
deleted file mode 100644
index 043e7ce8..00000000
--- a/contracts/lib/LICENCE
+++ /dev/null
@@ -1,22 +0,0 @@
-The MIT License (MIT)
-
-Copyright (c) 2016-2019 zOS Global Limited
-
-Permission is hereby granted, free of charge, to any person obtaining
-a copy of this software and associated documentation files (the
-"Software"), to deal in the Software without restriction, including
-without limitation the rights to use, copy, modify, merge, publish,
-distribute, sublicense, and/or sell copies of the Software, and to
-permit persons to whom the Software is furnished to do so, subject to
-the following conditions:
-
-The above copyright notice and this permission notice shall be included
-in all copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
-OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
-MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
-IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
-CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
-TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
-SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
\ No newline at end of file
diff --git a/contracts/mock/MockTokenHub.sol b/contracts/mock/MockTokenHub.sol
deleted file mode 100644
index 5754dccb..00000000
--- a/contracts/mock/MockTokenHub.sol
+++ /dev/null
@@ -1,66 +0,0 @@
-pragma solidity 0.6.4;
-
-import "../interface/ITokenHub.sol";
-
-contract MockTokenHub is ITokenHub {
-    bool panicBatchTransferOut;
-
-    bytes32 public constant BEP2_TOKEN_SYMBOL_FOR_BNB =
-        0x424E420000000000000000000000000000000000000000000000000000000000; // "BNB"
-
-    function getMiniRelayFee() external view override(ITokenHub) returns (uint256) {
-        return (1e16);
-    }
-
-    function getContractAddrByBEP2Symbol(bytes32) external view override(ITokenHub) returns (address) {
-        return address(0x0);
-    }
-
-    function getBep2SymbolByContractAddr(address) external view override(ITokenHub) returns (bytes32) {
-        return bytes32(0x0);
-    }
-
-    function bindToken(bytes32 bep2Symbol, address contractAddr, uint256 decimals) external override(ITokenHub) { }
-
-    function unbindToken(bytes32 bep2Symbol, address contractAddr) external override(ITokenHub) { }
-
-    function recoverBCAsset(bytes32, address, uint256) external override(ITokenHub) { }
-
-    function cancelTokenRecoverLock(bytes32, address) external override {
-        address TOKEN_RECOVER_PORTAL_ADDR = address(0x0000000000000000000000000000000000003000);
-        require(msg.sender == TOKEN_RECOVER_PORTAL_ADDR, "only token reover portal contract can call this function");
-    }
-
-    function transferOut(address, address, uint256, uint64) external payable override(ITokenHub) returns (bool) {
-        return true;
-    }
-
-    /* solium-disable-next-line */
-    function batchTransferOutBNB(
-        address[] calldata,
-        uint256[] calldata,
-        address[] calldata,
-        uint64
-    ) external payable override(ITokenHub) returns (bool) {
-        require(!panicBatchTransferOut, "panic in batchTransferOut");
-        return true;
-    }
-
-    function setPanicBatchTransferOut(bool doPanic) external {
-        panicBatchTransferOut = doPanic;
-    }
-
-    function withdrawStakingBNB(uint256 amount) external override returns (bool) {
-        address STAKING_CONTRACT_ADDR = address(0x0000000000000000000000000000000000002001);
-        require(msg.sender == STAKING_CONTRACT_ADDR, "only staking system contract can call this function");
-        if (amount != 0) {
-            payable(STAKING_CONTRACT_ADDR).transfer(amount);
-        }
-        return true;
-    }
-
-    function cancelTransferIn(address, address) external override {
-        address CROSS_CHAIN_CONTRACT_ADDR = address(0x0000000000000000000000000000000000002000);
-        require(msg.sender == CROSS_CHAIN_CONTRACT_ADDR, "only cross chain contract can call this function");
-    }
-}
diff --git a/package.json b/package.json
index a59595f0..deaac189 100644
--- a/package.json
+++ b/package.json
@@ -5,8 +5,8 @@
   "author": "",
   "license": "MIT",
   "scripts": {
-    "lint:check": "forge fmt ./contracts/BC_fusion --check",
-    "lint:write": "forge fmt ./contracts/BC_fusion",
+    "lint:check": "forge fmt ./contracts/BSCTimelock.sol ./contracts/GovToken.sol ./contracts/BSCGovernor.sol  ./contracts/TokenRecoverPortal.sol ./contracts/StakeCredit.sol ./contracts/StakeHub.sol ./contracts/SystemV2.sol --check",
+    "lint:write": "forge fmt ./contracts/BSCTimelock.sol ./contracts/GovToken.sol ./contracts/BSCGovernor.sol  ./contracts/TokenRecoverPortal.sol ./contracts/StakeCredit.sol ./contracts/StakeHub.sol ./contracts/SystemV2.sol ",
     "generate:mainnet": "poetry run python -m scripts.generate mainnet",
     "generate:testnet": "poetry run python -m scripts.generate testnet",
     "generate:dev": "poetry run python -m scripts.generate dev --epoch \"20\" --misdemeanor-threshold \"5\" --felony-threshold \"10\" --init-felony-slash-scope \"60\" --breathe-block-interval \"1 minutes\" --block-interval \"3 seconds\" --init-bc-consensus-addresses 'hex\"00000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000003000000000000000000000000f39fd6e51aad88f6f4ce6ab8827279cfffb9226600000000000000000000000070997970c51812dc3a010c7d01b50e0d17dc79c80000000000000000000000003c44cdddb6a900fa2b585dd299e03d12fa4293bc\"' --init-bc-vote-addresses 'hex\"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\"' --stake-hub-protector \"0xdF87F0e2B8519Ea2DD4aBd8B639cdD628497eD25\" --unbond-period \"2 minutes\" --downtime-jail-time \"2 minutes\" --felony-jail-time \"3 minutes\" --init-voting-delay \"1 minutes / BLOCK_INTERVAL\" --init-voting-period \"2 minutes / BLOCK_INTERVAL\" --init-min-period-after-quorum \"uint64(1 minutes / BLOCK_INTERVAL)\" --governor-protector \"0xdF87F0e2B8519Ea2DD4aBd8B639cdD628497eD25\" --init-minimal-delay \"1 minutes\" --lock-period-for-token-recover \"1 minutes\""
diff --git a/scripts/generate.py b/scripts/generate.py
index 0ea738d7..aab5f8c6 100644
--- a/scripts/generate.py
+++ b/scripts/generate.py
@@ -93,7 +93,7 @@ def generate_from_template(data, template_file, output_file):
 
 
 def generate_cross_chain(init_batch_size="50"):
-    contract = "CrossChain.sol"
+    contract = "deprecated/CrossChain.sol"
     backup_file(
         os.path.join(work_dir, "contracts", contract), os.path.join(work_dir, "contracts", contract[:-4] + ".bak")
     )
@@ -103,7 +103,7 @@ def generate_cross_chain(init_batch_size="50"):
 
 
 def generate_relayer_hub(whitelist_1, whitelist_2):
-    contract = "RelayerHub.sol"
+    contract = "deprecated/RelayerHub.sol"
     backup_file(
         os.path.join(work_dir, "contracts", contract), os.path.join(work_dir, "contracts", contract[:-4] + ".bak")
     )
@@ -134,7 +134,7 @@ def generate_stake_hub(
     breathe_block_interval, init_bc_consensus_addresses, init_bc_vote_addresses, max_elected_validators, unbond_period,
     downtime_jail_time, felony_jail_time, stake_hub_protector
 ):
-    contract = "BC_fusion/StakeHub.sol"
+    contract = "StakeHub.sol"
     backup_file(
         os.path.join(work_dir, "contracts", contract), os.path.join(work_dir, "contracts", contract[:-4] + ".bak")
     )
@@ -154,7 +154,7 @@ def generate_governor(
     block_interval, init_voting_delay, init_voting_period, init_proposal_threshold, init_quorum_numerator,
     propose_start_threshold, init_min_period_after_quorum, governor_protector
 ):
-    contract = "BC_fusion/BSCGovernor.sol"
+    contract = "BSCGovernor.sol"
     backup_file(
         os.path.join(work_dir, "contracts", contract), os.path.join(work_dir, "contracts", contract[:-4] + ".bak")
     )
@@ -174,7 +174,7 @@ def generate_governor(
 
 
 def generate_timelock(init_minimal_delay):
-    contract = "BC_fusion/BSCTimelock.sol"
+    contract = "BSCTimelock.sol"
     backup_file(
         os.path.join(work_dir, "contracts", contract), os.path.join(work_dir, "contracts", contract[:-4] + ".bak")
     )
@@ -204,7 +204,7 @@ def generate_system_reward():
 
 
 def generate_tendermint_light_client(init_consensus_state_bytes, init_reward_for_validator_ser_change="1e16"):
-    contract = "TendermintLightClient.sol"
+    contract = "deprecated/TendermintLightClient.sol"
     backup_file(
         os.path.join(work_dir, "contracts", contract), os.path.join(work_dir, "contracts", contract[:-4] + ".bak")
     )
@@ -230,7 +230,7 @@ def generate_token_hub(lock_period_for_token_recover):
 
 
 def generate_token_recover_portal(source_chain_id, token_recover_portal_protector):
-    contract = "BC_fusion/TokenRecoverPortal.sol"
+    contract = "TokenRecoverPortal.sol"
     backup_file(
         os.path.join(work_dir, "contracts", contract), os.path.join(work_dir, "contracts", contract[:-4] + ".bak")
     )
@@ -515,7 +515,7 @@ def recover():
             shutil.copyfile(os.path.join(contracts_dir, file), os.path.join(contracts_dir, c_file))
             os.remove(os.path.join(contracts_dir, file))
 
-    contracts_dir = os.path.join(contracts_dir, "BC_fusion")
+    contracts_dir = os.path.join(contracts_dir, "deprecated")
     for file in os.listdir(contracts_dir):
         if file.endswith(".bak"):
             c_file = file[:-4] + ".sol"
@@ -573,7 +573,7 @@ def generate_validators(
 
 
 @main.command(help="Generate errors signature")
-def generate_error_sig(dir_path: str = "./contracts/BC_fusion"):
+def generate_error_sig(dir_path: str = "./contracts"):
     dir_path = os.path.join(work_dir, dir_path)
 
     annotation_prefix = "    // @notice signature: "
diff --git a/test/Governor.t.sol b/test/Governor.t.sol
index 10f70e1c..8878a51e 100644
--- a/test/Governor.t.sol
+++ b/test/Governor.t.sol
@@ -94,7 +94,7 @@ contract GovernorTest is Deployer {
             "updateParam(string,bytes,address)", "votingDelay", abi.encodePacked(newVotingDelay), GOVERNOR_ADDR
         );
 
-//        assertEq(governor.proposeStarted(), true, "propose should not start");
+        //        assertEq(governor.proposeStarted(), true, "propose should not start");
 
         // mainnet totalSupply is already enough
         // // govBNB totalSupply not enough
diff --git a/test/SlashIndicator.t.sol b/test/SlashIndicator.t.sol
index 5d056061..3ebdcf74 100644
--- a/test/SlashIndicator.t.sol
+++ b/test/SlashIndicator.t.sol
@@ -139,10 +139,10 @@ contract SlashIndicatorTest is Deployer {
         vm.prank(validatorLast);
         // can not avoid downtime slash by reducing gasLimit
         vm.expectRevert();
-        bscValidatorSet.exitMaintenance{gas: 550000 }();
+        bscValidatorSet.exitMaintenance{ gas: 550000 }();
 
         vm.prank(validatorLast);
-        bscValidatorSet.exitMaintenance{gas: 1000000 }();
+        bscValidatorSet.exitMaintenance{ gas: 1000000 }();
     }
 
     function testMaintenanceFix2() public {
@@ -150,7 +150,7 @@ contract SlashIndicatorTest is Deployer {
         uint256 numOfMaintainingBefore = bscValidatorSet.numOfMaintaining();
         assert(bscValidatorSet.isCurrentValidator(validatorLast));
 
-        (uint256 misdemeanorThreshold, ) = slashIndicator.getSlashThresholds();
+        (uint256 misdemeanorThreshold,) = slashIndicator.getSlashThresholds();
         (, uint256 countBefore) = slashIndicator.getSlashIndicator(validatorLast);
 
         uint256 height = block.number;
diff --git a/test/StakeHub.t.sol b/test/StakeHub.t.sol
index 92d42b43..79c08d7e 100644
--- a/test/StakeHub.t.sol
+++ b/test/StakeHub.t.sol
@@ -786,7 +786,7 @@ contract StakeHubTest is Deployer {
         // edit vote address
         vm.warp(block.timestamp + 1 days);
         bytes memory newVoteAddress =
-        hex"000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001234";
+            hex"000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001234";
         bytes memory blsProof = new bytes(96);
         vm.expectEmit(true, false, false, true, address(stakeHub));
         emit VoteAddressEdited(validator, newVoteAddress);