diff --git a/hardhat-test/GasSwap.spec.ts b/hardhat-test/GasSwap.spec.ts
deleted file mode 100644
index 4c98ab4a..00000000
--- a/hardhat-test/GasSwap.spec.ts
+++ /dev/null
@@ -1,329 +0,0 @@
-/* eslint-disable node/no-unpublished-import */
-/* eslint-disable node/no-missing-import */
-import { HardhatEthersSigner } from "@nomicfoundation/hardhat-ethers/signers";
-import { expect } from "chai";
-import { MaxUint256, Signature, ZeroAddress, ZeroHash, toBigInt } from "ethers";
-import { ethers } from "hardhat";
-
-import { GasSwap, ERC2771Forwarder, MockERC20, MockGasSwapTarget } from "../typechain";
-
-describe("GasSwap.spec", async () => {
-  let deployer: HardhatEthersSigner;
-  let signer: HardhatEthersSigner;
-
-  let forwarder: ERC2771Forwarder;
-  let swap: GasSwap;
-  let target: MockGasSwapTarget;
-  let token: MockERC20;
-
-  beforeEach(async () => {
-    [deployer, signer] = await ethers.getSigners();
-
-    const ERC2771Forwarder = await ethers.getContractFactory("ERC2771Forwarder", deployer);
-    forwarder = await ERC2771Forwarder.deploy("ERC2771Forwarder");
-
-    const GasSwap = await ethers.getContractFactory("GasSwap", deployer);
-    swap = await GasSwap.deploy(forwarder.getAddress());
-
-    const MockGasSwapTarget = await ethers.getContractFactory("MockGasSwapTarget", deployer);
-    target = await MockGasSwapTarget.deploy();
-
-    const MockERC20 = await ethers.getContractFactory("MockERC20", deployer);
-    token = await MockERC20.deploy("x", "y", 18);
-  });
-
-  context("auth", async () => {
-    it("should initialize correctly", async () => {
-      expect(await swap.owner()).to.eq(deployer.address);
-    });
-
-    context("#updateFeeRatio", async () => {
-      it("should revert, when non-owner call", async () => {
-        await expect(swap.connect(signer).updateFeeRatio(1)).to.revertedWith("Ownable: caller is not the owner");
-      });
-
-      it("should succeed", async () => {
-        expect(await swap.feeRatio()).to.eq(ZeroAddress);
-        await expect(swap.updateFeeRatio(100)).to.emit(swap, "UpdateFeeRatio").withArgs(100);
-        expect(await swap.feeRatio()).to.eq(100);
-      });
-    });
-
-    context("#updateApprovedTarget", async () => {
-      it("should revert, when non-owner call", async () => {
-        await expect(swap.connect(signer).updateApprovedTarget(target.getAddress(), false)).to.revertedWith(
-          "Ownable: caller is not the owner"
-        );
-      });
-
-      it("should succeed", async () => {
-        expect(await swap.approvedTargets(target.getAddress())).to.eq(false);
-        await expect(swap.updateApprovedTarget(target.getAddress(), true))
-          .to.emit(swap, "UpdateApprovedTarget")
-          .withArgs(await target.getAddress(), true);
-        expect(await swap.approvedTargets(target.getAddress())).to.eq(true);
-        await expect(swap.updateApprovedTarget(target.getAddress(), false))
-          .to.emit(swap, "UpdateApprovedTarget")
-          .withArgs(await target.getAddress(), false);
-        expect(await swap.approvedTargets(target.getAddress())).to.eq(false);
-      });
-    });
-
-    context("#withdraw", async () => {
-      it("should revert, when non-owner call", async () => {
-        await expect(swap.connect(signer).withdraw(ZeroAddress, 0)).to.revertedWith("Ownable: caller is not the owner");
-      });
-
-      it("should succeed, when withdraw ETH", async () => {
-        await deployer.sendTransaction({ to: swap.getAddress(), value: ethers.parseEther("1") });
-        const balanceBefore = await ethers.provider.getBalance(deployer.address);
-        const tx = await swap.withdraw(ZeroAddress, ethers.parseEther("1"));
-        const receipt = await tx.wait();
-        const balanceAfter = await ethers.provider.getBalance(deployer.address);
-        expect(balanceAfter - balanceBefore).to.eq(ethers.parseEther("1") - receipt!.gasUsed * receipt!.gasPrice);
-      });
-
-      it("should succeed, when withdraw token", async () => {
-        await token.mint(swap.getAddress(), ethers.parseEther("1"));
-        const balanceBefore = await token.balanceOf(deployer.address);
-        await swap.withdraw(token.getAddress(), ethers.parseEther("1"));
-        const balanceAfter = await token.balanceOf(deployer.address);
-        expect(balanceAfter - balanceBefore).to.eq(ethers.parseEther("1"));
-      });
-    });
-  });
-
-  const permit = async (amount: bigint) => {
-    const value = {
-      owner: signer.address,
-      spender: await swap.getAddress(),
-      value: amount,
-      nonce: await token.nonces(signer.address),
-      deadline: MaxUint256,
-    };
-
-    const domain = {
-      name: await token.name(),
-      version: "1",
-      chainId: (await ethers.provider.getNetwork()).chainId,
-      verifyingContract: await token.getAddress(),
-    };
-
-    const types = {
-      Permit: [
-        {
-          name: "owner",
-          type: "address",
-        },
-        {
-          name: "spender",
-          type: "address",
-        },
-        {
-          name: "value",
-          type: "uint256",
-        },
-        {
-          name: "nonce",
-          type: "uint256",
-        },
-        {
-          name: "deadline",
-          type: "uint256",
-        },
-      ],
-    };
-
-    const signature = Signature.from(await signer.signTypedData(domain, types, value));
-    return signature;
-  };
-
-  context("swap", async () => {
-    it("should revert, when target not approved", async () => {
-      await expect(
-        swap.swap(
-          {
-            token: token.getAddress(),
-            value: 0,
-            deadline: 0,
-            r: ZeroHash,
-            s: ZeroHash,
-            v: 0,
-          },
-          {
-            target: target.getAddress(),
-            data: "0x",
-            minOutput: 0,
-          }
-        )
-      ).to.revertedWith("target not approved");
-    });
-
-    it("should revert, when insufficient output amount", async () => {
-      const amountIn = ethers.parseEther("1");
-      const amountOut = ethers.parseEther("2");
-      await token.mint(signer.address, amountIn);
-      await deployer.sendTransaction({ to: target.getAddress(), value: amountOut });
-      const signature = await permit(amountIn);
-
-      await target.setToken(token.getAddress());
-      await target.setAmountIn(amountIn);
-
-      await swap.updateApprovedTarget(target.getAddress(), true);
-      await expect(
-        swap.connect(signer).swap(
-          {
-            token: await token.getAddress(),
-            value: amountIn,
-            deadline: MaxUint256,
-            r: signature.r,
-            s: signature.s,
-            v: signature.v,
-          },
-          {
-            target: target.getAddress(),
-            data: "0x8119c065",
-            minOutput: amountOut + 1n,
-          }
-        )
-      ).to.revertedWith("insufficient output amount");
-    });
-
-    for (const refundRatio of [0n, 1n, 5n]) {
-      for (const feeRatio of ["0", "5", "50"]) {
-        it(`should succeed, when swap by signer directly, with feeRatio[${feeRatio}%] refundRatio[${refundRatio}%]`, async () => {
-          const amountIn = ethers.parseEther("1");
-          const amountOut = ethers.parseEther("2");
-          await token.mint(signer.address, amountIn);
-          await deployer.sendTransaction({ to: target.getAddress(), value: amountOut });
-          const signature = await permit(amountIn);
-
-          await target.setToken(token.getAddress());
-          await target.setAmountIn(amountIn);
-          await target.setRefund((amountIn * refundRatio) / 100n);
-
-          await swap.updateApprovedTarget(target.getAddress(), true);
-          await swap.updateFeeRatio(ethers.parseEther(feeRatio) / 100n);
-          const fee = (amountOut * toBigInt(feeRatio)) / 100n;
-
-          const balanceBefore = await ethers.provider.getBalance(signer.address);
-          const tx = await swap.connect(signer).swap(
-            {
-              token: await token.getAddress(),
-              value: amountIn,
-              deadline: MaxUint256,
-              r: signature.r,
-              s: signature.s,
-              v: signature.v,
-            },
-            {
-              target: target.getAddress(),
-              data: "0x8119c065",
-              minOutput: amountOut - fee,
-            }
-          );
-          const receipt = await tx.wait();
-          const balanceAfter = await ethers.provider.getBalance(signer.address);
-          expect(balanceAfter - balanceBefore).to.eq(amountOut - fee - receipt!.gasUsed * receipt!.gasPrice);
-          expect(await token.balanceOf(signer.address)).to.eq((amountIn * refundRatio) / 100n);
-        });
-
-        it(`should succeed, when swap by signer with forwarder, with feeRatio[${feeRatio}%] refundRatio[${refundRatio}%]`, async () => {
-          const amountIn = ethers.parseEther("1");
-          const amountOut = ethers.parseEther("2");
-          await token.mint(signer.address, amountIn);
-          await deployer.sendTransaction({ to: await target.getAddress(), value: amountOut });
-          const permitSignature = await permit(amountIn);
-
-          await target.setToken(token.getAddress());
-          await target.setAmountIn(amountIn);
-          await target.setRefund((amountIn * refundRatio) / 100n);
-
-          await swap.updateApprovedTarget(target.getAddress(), true);
-          await swap.updateFeeRatio(ethers.parseEther(feeRatio) / 100n);
-          const fee = (amountOut * toBigInt(feeRatio)) / 100n;
-
-          const reqWithoutSignature = {
-            from: signer.address,
-            to: await swap.getAddress(),
-            value: 0n,
-            gas: 1000000,
-            nonce: await forwarder.nonces(signer.address),
-            deadline: 2000000000,
-            data: swap.interface.encodeFunctionData("swap", [
-              {
-                token: await token.getAddress(),
-                value: amountIn,
-                deadline: MaxUint256,
-                r: permitSignature.r,
-                s: permitSignature.s,
-                v: permitSignature.v,
-              },
-              {
-                target: await target.getAddress(),
-                data: "0x8119c065",
-                minOutput: amountOut - fee,
-              },
-            ]),
-          };
-
-          const signature = await signer.signTypedData(
-            {
-              name: "ERC2771Forwarder",
-              version: "1",
-              chainId: (await ethers.provider.getNetwork()).chainId,
-              verifyingContract: await forwarder.getAddress(),
-            },
-            {
-              ForwardRequest: [
-                {
-                  name: "from",
-                  type: "address",
-                },
-                {
-                  name: "to",
-                  type: "address",
-                },
-                {
-                  name: "value",
-                  type: "uint256",
-                },
-                {
-                  name: "gas",
-                  type: "uint256",
-                },
-                {
-                  name: "nonce",
-                  type: "uint256",
-                },
-                {
-                  name: "deadline",
-                  type: "uint48",
-                },
-                {
-                  name: "data",
-                  type: "bytes",
-                },
-              ],
-            },
-            reqWithoutSignature
-          );
-
-          const balanceBefore = await ethers.provider.getBalance(signer.address);
-          await forwarder.execute({
-            from: reqWithoutSignature.from,
-            to: reqWithoutSignature.to,
-            value: reqWithoutSignature.value,
-            gas: reqWithoutSignature.gas,
-            deadline: reqWithoutSignature.deadline,
-            data: reqWithoutSignature.data,
-            signature,
-          });
-          const balanceAfter = await ethers.provider.getBalance(signer.address);
-          expect(balanceAfter - balanceBefore).to.eq(amountOut - fee);
-          expect(await token.balanceOf(signer.address)).to.eq((amountIn * refundRatio) / 100n);
-        });
-      }
-    }
-  });
-});
diff --git a/src/L1/IL1ScrollMessenger.sol b/src/L1/IL1ScrollMessenger.sol
index 4a8f2b9f..dac1c8ce 100644
--- a/src/L1/IL1ScrollMessenger.sol
+++ b/src/L1/IL1ScrollMessenger.sol
@@ -62,18 +62,4 @@ interface IL1ScrollMessenger is IScrollMessenger {
         uint32 newGasLimit,
         address refundAddress
     ) external payable;
-
-    /// @notice Drop a skipped message.
-    /// @param from The address of the sender of the message.
-    /// @param to The address of the recipient of the message.
-    /// @param value The msg.value passed to the message call.
-    /// @param messageNonce The nonce for the message to drop.
-    /// @param message The content of the message.
-    function dropMessage(
-        address from,
-        address to,
-        uint256 value,
-        uint256 messageNonce,
-        bytes memory message
-    ) external;
 }
diff --git a/src/L1/L1ScrollMessenger.sol b/src/L1/L1ScrollMessenger.sol
index a54f467c..15bde04a 100644
--- a/src/L1/L1ScrollMessenger.sol
+++ b/src/L1/L1ScrollMessenger.sol
@@ -10,8 +10,6 @@ import {IScrollMessenger} from "../libraries/IScrollMessenger.sol";
 import {ScrollMessengerBase} from "../libraries/ScrollMessengerBase.sol";
 import {WithdrawTrieVerifier} from "../libraries/verifier/WithdrawTrieVerifier.sol";
 
-import {IMessageDropCallback} from "../libraries/callbacks/IMessageDropCallback.sol";
-
 // solhint-disable avoid-low-level-calls
 // solhint-disable not-rely-on-time
 // solhint-disable reason-string
@@ -78,6 +76,8 @@ contract L1ScrollMessenger is ScrollMessengerBase, IL1ScrollMessenger {
     mapping(bytes32 => bool) public isL2MessageExecuted;
 
     /// @notice Mapping from L1 message hash to drop status.
+    /// @custom:deprecated This is no longer used.
+    // slither-disable-next-line uninitialized-state
     mapping(bytes32 => bool) public isL1MessageDropped;
 
     /// @dev The storage slot used as Rollup contract, which is deprecated now.
@@ -281,64 +281,6 @@ contract L1ScrollMessenger is ScrollMessengerBase, IL1ScrollMessenger {
         }
     }
 
-    /// @inheritdoc IL1ScrollMessenger
-    /// @dev Since we don't skip any messages in `L1MessageQueueV2`, only messages from `L1MessageQueueV1` can be dropped.
-    function dropMessage(
-        address _from,
-        address _to,
-        uint256 _value,
-        uint256 _messageNonce,
-        bytes memory _message
-    ) external override whenNotPaused notInExecution {
-        // The criteria for dropping a message:
-        // 1. The message is a L1 message.
-        // 2. The message has not been dropped before.
-        // 3. the message and all of its replacement are finalized in L1.
-        // 4. the message and all of its replacement are skipped.
-        //
-        // Possible denial of service attack:
-        // + replayMessage is called every time someone want to drop the message.
-        // + replayMessage is called so many times for a skipped message, thus results a long list.
-        //
-        // We limit the number of `replayMessage` calls of each message, which may solve the above problem.
-
-        // check message exists
-        bytes memory _xDomainCalldata = _encodeXDomainCalldata(_from, _to, _value, _messageNonce, _message);
-        bytes32 _xDomainCalldataHash = keccak256(_xDomainCalldata);
-        require(messageSendTimestamp[_xDomainCalldataHash] > 0, "Provided message has not been enqueued");
-
-        // check message not dropped
-        require(!isL1MessageDropped[_xDomainCalldataHash], "Message already dropped");
-
-        // check message is finalized
-        uint256 _lastIndex = replayStates[_xDomainCalldataHash].lastIndex;
-        if (_lastIndex == 0) _lastIndex = _messageNonce;
-
-        // check message is skipped and drop it.
-        // @note If the list is very long, the message may never be dropped.
-        while (true) {
-            // If the `_lastIndex` is from `messageQueueV2`, it will revert in `messageQueueV1.dropCrossDomainMessage`.
-            // call to messageQueueV1 is safe.
-            // slither-disable-next-line reentrancy-no-eth
-            IL1MessageQueueV1(messageQueueV1).dropCrossDomainMessage(_lastIndex);
-            _lastIndex = prevReplayIndex[_lastIndex];
-            if (_lastIndex == 0) break;
-            unchecked {
-                _lastIndex = _lastIndex - 1;
-            }
-        }
-
-        isL1MessageDropped[_xDomainCalldataHash] = true;
-
-        // set execution context
-        xDomainMessageSender = ScrollConstants.DROP_XDOMAIN_MESSAGE_SENDER;
-        // xDomainMessageSender serves as reentrancy guard (notInExecution modifier).
-        // slither-disable-next-line reentrancy-eth
-        IMessageDropCallback(_from).onDropMessage{value: _value}(_message);
-        // clear execution context
-        xDomainMessageSender = ScrollConstants.DEFAULT_XDOMAIN_MESSAGE_SENDER;
-    }
-
     /************************
      * Restricted Functions *
      ************************/
diff --git a/src/L1/gateways/L1ERC1155Gateway.sol b/src/L1/gateways/L1ERC1155Gateway.sol
index 794d43ce..9b0b4162 100644
--- a/src/L1/gateways/L1ERC1155Gateway.sol
+++ b/src/L1/gateways/L1ERC1155Gateway.sol
@@ -9,7 +9,6 @@ import {IL2ERC1155Gateway} from "../../L2/gateways/IL2ERC1155Gateway.sol";
 import {IL1ScrollMessenger} from "../IL1ScrollMessenger.sol";
 import {IL1ERC1155Gateway} from "./IL1ERC1155Gateway.sol";
 
-import {IMessageDropCallback} from "../../libraries/callbacks/IMessageDropCallback.sol";
 import {ScrollGatewayBase} from "../../libraries/gateway/ScrollGatewayBase.sol";
 
 /// @title L1ERC1155Gateway
@@ -19,7 +18,7 @@ import {ScrollGatewayBase} from "../../libraries/gateway/ScrollGatewayBase.sol";
 /// NFT will be transfer to the recipient directly.
 ///
 /// This will be changed if we have more specific scenarios.
-contract L1ERC1155Gateway is ERC1155HolderUpgradeable, ScrollGatewayBase, IL1ERC1155Gateway, IMessageDropCallback {
+contract L1ERC1155Gateway is ERC1155HolderUpgradeable, ScrollGatewayBase, IL1ERC1155Gateway {
     /**********
      * Events *
      **********/
@@ -139,31 +138,6 @@ contract L1ERC1155Gateway is ERC1155HolderUpgradeable, ScrollGatewayBase, IL1ERC
         emit FinalizeBatchWithdrawERC1155(_l1Token, _l2Token, _from, _to, _tokenIds, _amounts);
     }
 
-    /// @inheritdoc IMessageDropCallback
-    function onDropMessage(bytes calldata _message) external payable virtual onlyInDropContext nonReentrant {
-        require(msg.value == 0, "nonzero msg.value");
-
-        if (bytes4(_message[0:4]) == IL2ERC1155Gateway.finalizeDepositERC1155.selector) {
-            (address _token, , address _sender, , uint256 _tokenId, uint256 _amount) = abi.decode(
-                _message[4:],
-                (address, address, address, address, uint256, uint256)
-            );
-            IERC1155Upgradeable(_token).safeTransferFrom(address(this), _sender, _tokenId, _amount, "");
-
-            emit RefundERC1155(_token, _sender, _tokenId, _amount);
-        } else if (bytes4(_message[0:4]) == IL2ERC1155Gateway.finalizeBatchDepositERC1155.selector) {
-            (address _token, , address _sender, , uint256[] memory _tokenIds, uint256[] memory _amounts) = abi.decode(
-                _message[4:],
-                (address, address, address, address, uint256[], uint256[])
-            );
-            IERC1155Upgradeable(_token).safeBatchTransferFrom(address(this), _sender, _tokenIds, _amounts, "");
-
-            emit BatchRefundERC1155(_token, _sender, _tokenIds, _amounts);
-        } else {
-            revert("invalid selector");
-        }
-    }
-
     /************************
      * Restricted Functions *
      ************************/
diff --git a/src/L1/gateways/L1ERC20Gateway.sol b/src/L1/gateways/L1ERC20Gateway.sol
index 42c51144..c9c5820a 100644
--- a/src/L1/gateways/L1ERC20Gateway.sol
+++ b/src/L1/gateways/L1ERC20Gateway.sol
@@ -10,12 +10,11 @@ import {IL1GatewayRouter} from "./IL1GatewayRouter.sol";
 
 import {IL2ERC20Gateway} from "../../L2/gateways/IL2ERC20Gateway.sol";
 import {ScrollGatewayBase} from "../../libraries/gateway/ScrollGatewayBase.sol";
-import {IMessageDropCallback} from "../../libraries/callbacks/IMessageDropCallback.sol";
 
 /// @title L1ERC20Gateway
 /// @notice The `L1ERC20Gateway` as a base contract for ERC20 gateways in L1.
 /// It has implementation of common used functions for ERC20 gateways.
-abstract contract L1ERC20Gateway is IL1ERC20Gateway, IMessageDropCallback, ScrollGatewayBase {
+abstract contract L1ERC20Gateway is IL1ERC20Gateway, ScrollGatewayBase {
     using SafeERC20Upgradeable for IERC20Upgradeable;
 
     /*************
@@ -79,25 +78,6 @@ abstract contract L1ERC20Gateway is IL1ERC20Gateway, IMessageDropCallback, Scrol
         emit FinalizeWithdrawERC20(_l1Token, _l2Token, _from, _to, _amount, _data);
     }
 
-    /// @inheritdoc IMessageDropCallback
-    function onDropMessage(bytes calldata _message) external payable virtual onlyInDropContext nonReentrant {
-        // _message should start with 0x8431f5c1  =>  finalizeDepositERC20(address,address,address,address,uint256,bytes)
-        require(bytes4(_message[0:4]) == IL2ERC20Gateway.finalizeDepositERC20.selector, "invalid selector");
-
-        // decode (token, receiver, amount)
-        (address _token, , address _receiver, , uint256 _amount, ) = abi.decode(
-            _message[4:],
-            (address, address, address, address, uint256, bytes)
-        );
-
-        // do dome check for each custom gateway
-        _beforeDropMessage(_token, _receiver, _amount);
-
-        IERC20Upgradeable(_token).safeTransfer(_receiver, _amount);
-
-        emit RefundERC20(_token, _receiver, _amount);
-    }
-
     /**********************
      * Internal Functions *
      **********************/
diff --git a/src/L1/gateways/L1ERC721Gateway.sol b/src/L1/gateways/L1ERC721Gateway.sol
index f8ee6113..9055512b 100644
--- a/src/L1/gateways/L1ERC721Gateway.sol
+++ b/src/L1/gateways/L1ERC721Gateway.sol
@@ -9,7 +9,6 @@ import {IL2ERC721Gateway} from "../../L2/gateways/IL2ERC721Gateway.sol";
 import {IL1ScrollMessenger} from "../IL1ScrollMessenger.sol";
 import {IL1ERC721Gateway} from "./IL1ERC721Gateway.sol";
 
-import {IMessageDropCallback} from "../../libraries/callbacks/IMessageDropCallback.sol";
 import {ScrollGatewayBase} from "../../libraries/gateway/ScrollGatewayBase.sol";
 
 /// @title L1ERC721Gateway
@@ -19,7 +18,7 @@ import {ScrollGatewayBase} from "../../libraries/gateway/ScrollGatewayBase.sol";
 /// NFT will be transfer to the recipient directly.
 ///
 /// This will be changed if we have more specific scenarios.
-contract L1ERC721Gateway is ERC721HolderUpgradeable, ScrollGatewayBase, IL1ERC721Gateway, IMessageDropCallback {
+contract L1ERC721Gateway is ERC721HolderUpgradeable, ScrollGatewayBase, IL1ERC721Gateway {
     /**********
      * Events *
      **********/
@@ -137,32 +136,6 @@ contract L1ERC721Gateway is ERC721HolderUpgradeable, ScrollGatewayBase, IL1ERC72
         emit FinalizeBatchWithdrawERC721(_l1Token, _l2Token, _from, _to, _tokenIds);
     }
 
-    /// @inheritdoc IMessageDropCallback
-    function onDropMessage(bytes calldata _message) external payable virtual onlyInDropContext nonReentrant {
-        require(msg.value == 0, "nonzero msg.value");
-
-        if (bytes4(_message[0:4]) == IL2ERC721Gateway.finalizeDepositERC721.selector) {
-            (address _token, , address _receiver, , uint256 _tokenId) = abi.decode(
-                _message[4:],
-                (address, address, address, address, uint256)
-            );
-            IERC721Upgradeable(_token).safeTransferFrom(address(this), _receiver, _tokenId);
-
-            emit RefundERC721(_token, _receiver, _tokenId);
-        } else if (bytes4(_message[0:4]) == IL2ERC721Gateway.finalizeBatchDepositERC721.selector) {
-            (address _token, , address _receiver, , uint256[] memory _tokenIds) = abi.decode(
-                _message[4:],
-                (address, address, address, address, uint256[])
-            );
-            for (uint256 i = 0; i < _tokenIds.length; i++) {
-                IERC721Upgradeable(_token).safeTransferFrom(address(this), _receiver, _tokenIds[i]);
-            }
-            emit BatchRefundERC721(_token, _receiver, _tokenIds);
-        } else {
-            revert("invalid selector");
-        }
-    }
-
     /************************
      * Restricted Functions *
      ************************/
diff --git a/src/L1/gateways/L1ETHGateway.sol b/src/L1/gateways/L1ETHGateway.sol
index 09c41ff9..e6e4a5a4 100644
--- a/src/L1/gateways/L1ETHGateway.sol
+++ b/src/L1/gateways/L1ETHGateway.sol
@@ -6,7 +6,6 @@ import {IL2ETHGateway} from "../../L2/gateways/IL2ETHGateway.sol";
 import {IL1ScrollMessenger} from "../IL1ScrollMessenger.sol";
 import {IL1ETHGateway} from "./IL1ETHGateway.sol";
 
-import {IMessageDropCallback} from "../../libraries/callbacks/IMessageDropCallback.sol";
 import {ScrollGatewayBase} from "../../libraries/gateway/ScrollGatewayBase.sol";
 
 // solhint-disable avoid-low-level-calls
@@ -16,7 +15,7 @@ import {ScrollGatewayBase} from "../../libraries/gateway/ScrollGatewayBase.sol";
 /// finalize withdraw ETH from layer 2.
 /// @dev The deposited ETH tokens are held in this gateway. On finalizing withdraw, the corresponding
 /// ETH will be transfer to the recipient directly.
-contract L1ETHGateway is ScrollGatewayBase, IL1ETHGateway, IMessageDropCallback {
+contract L1ETHGateway is ScrollGatewayBase, IL1ETHGateway {
     /***************
      * Constructor *
      ***************/
@@ -100,24 +99,6 @@ contract L1ETHGateway is ScrollGatewayBase, IL1ETHGateway, IMessageDropCallback
         emit FinalizeWithdrawETH(_from, _to, _amount, _data);
     }
 
-    /// @inheritdoc IMessageDropCallback
-    function onDropMessage(bytes calldata _message) external payable virtual onlyInDropContext nonReentrant {
-        // _message should start with 0x232e8748  =>  finalizeDepositETH(address,address,uint256,bytes)
-        require(bytes4(_message[0:4]) == IL2ETHGateway.finalizeDepositETH.selector, "invalid selector");
-
-        // decode (receiver, amount)
-        (address _receiver, , uint256 _amount, ) = abi.decode(_message[4:], (address, address, uint256, bytes));
-
-        require(_amount == msg.value, "msg.value mismatch");
-
-        // no reentrancy risk (nonReentrant modifier).
-        // slither-disable-next-line arbitrary-send-eth
-        (bool _success, ) = _receiver.call{value: _amount}("");
-        require(_success, "ETH transfer failed");
-
-        emit RefundETH(_receiver, _amount);
-    }
-
     /**********************
      * Internal Functions *
      **********************/
diff --git a/src/L1/rollup/IL1MessageQueueV1.sol b/src/L1/rollup/IL1MessageQueueV1.sol
index e90b60c7..41c2de8e 100644
--- a/src/L1/rollup/IL1MessageQueueV1.sol
+++ b/src/L1/rollup/IL1MessageQueueV1.sol
@@ -2,6 +2,7 @@
 
 pragma solidity ^0.8.24;
 
+/// @custom:deprecated This contract is no longer used in production.
 interface IL1MessageQueueV1 {
     /**********
      * Events *
@@ -63,26 +64,32 @@ interface IL1MessageQueueV1 {
      *************************/
 
     /// @notice The start index of all pending inclusion messages.
+    /// @custom:deprecated Please use `IL1MessageQueueV2.pendingQueueIndex` instead.
     function pendingQueueIndex() external view returns (uint256);
 
     /// @notice The start index of all unfinalized messages.
     /// @dev All messages from `nextUnfinalizedQueueIndex` to `pendingQueueIndex-1` are committed but not finalized.
+    /// @custom:deprecated Please use `IL1MessageQueueV2.nextUnfinalizedQueueIndex` instead.
     function nextUnfinalizedQueueIndex() external view returns (uint256);
 
     /// @notice Return the index of next appended message.
     /// @dev Also the total number of appended messages.
+    /// @custom:deprecated Please use `IL1MessageQueueV2.nextCrossDomainMessageIndex` instead.
     function nextCrossDomainMessageIndex() external view returns (uint256);
 
     /// @notice Return the message of in `queueIndex`.
     /// @param queueIndex The index to query.
+    /// @custom:deprecated Please use `IL1MessageQueueV2.getCrossDomainMessage` instead.
     function getCrossDomainMessage(uint256 queueIndex) external view returns (bytes32);
 
     /// @notice Return the amount of ETH should pay for cross domain message.
     /// @param gasLimit Gas limit required to complete the message relay on L2.
+    /// @custom:deprecated Please use `IL1MessageQueueV2.estimateCrossDomainMessageFee` instead.
     function estimateCrossDomainMessageFee(uint256 gasLimit) external view returns (uint256);
 
     /// @notice Return the amount of intrinsic gas fee should pay for cross domain message.
     /// @param _calldata The calldata of L1-initiated transaction.
+    /// @custom:deprecated Please use `IL1MessageQueueV2.calculateIntrinsicGasFee` instead.
     function calculateIntrinsicGasFee(bytes calldata _calldata) external view returns (uint256);
 
     /// @notice Return the hash of a L1 message.
@@ -92,6 +99,7 @@ interface IL1MessageQueueV1 {
     /// @param target The address of target.
     /// @param gasLimit The gas limit provided.
     /// @param data The calldata passed to target address.
+    /// @custom:deprecated Please use `IL1MessageQueueV2.computeTransactionHash` instead.
     function computeTransactionHash(
         address sender,
         uint256 queueIndex,
@@ -103,10 +111,12 @@ interface IL1MessageQueueV1 {
 
     /// @notice Return whether the message is skipped.
     /// @param queueIndex The queue index of the message to check.
+    /// @custom:deprecated
     function isMessageSkipped(uint256 queueIndex) external view returns (bool);
 
     /// @notice Return whether the message is dropped.
     /// @param queueIndex The queue index of the message to check.
+    /// @custom:deprecated
     function isMessageDropped(uint256 queueIndex) external view returns (bool);
 
     /*****************************
@@ -117,6 +127,7 @@ interface IL1MessageQueueV1 {
     /// @param target The address of target contract to call in L2.
     /// @param gasLimit The maximum gas should be used for relay this message in L2.
     /// @param data The calldata passed to target contract.
+    /// @custom:deprecated Please use `IL1MessageQueueV2.appendCrossDomainMessage` instead.
     function appendCrossDomainMessage(
         address target,
         uint256 gasLimit,
@@ -130,6 +141,7 @@ interface IL1MessageQueueV1 {
     /// @param value The value passed
     /// @param gasLimit The maximum gas should be used for this transaction in L2.
     /// @param data The calldata passed to target contract.
+    /// @custom:deprecated Please use `IL1MessageQueueV2.appendEnforcedTransaction` instead.
     function appendEnforcedTransaction(
         address sender,
         address target,
@@ -146,6 +158,7 @@ interface IL1MessageQueueV1 {
     /// @param startIndex The start index to pop.
     /// @param count The number of messages to pop.
     /// @param skippedBitmap A bitmap indicates whether a message is skipped.
+    /// @custom:deprecated
     function popCrossDomainMessage(
         uint256 startIndex,
         uint256 count,
@@ -157,12 +170,15 @@ interface IL1MessageQueueV1 {
     /// @dev We can only reset unfinalized popped messages.
     ///
     /// @param startIndex The start index to reset.
+    /// @custom:deprecated
     function resetPoppedCrossDomainMessage(uint256 startIndex) external;
 
     /// @notice Finalize status of popped messages.
     /// @param newFinalizedQueueIndexPlusOne The index of message to finalize plus one.
+    /// @custom:deprecated
     function finalizePoppedCrossDomainMessage(uint256 newFinalizedQueueIndexPlusOne) external;
 
     /// @notice Drop a skipped message from the queue.
+    /// @custom:deprecated
     function dropCrossDomainMessage(uint256 index) external;
 }
diff --git a/src/L1/rollup/IL1MessageQueueWithGasPriceOracle.sol b/src/L1/rollup/IL1MessageQueueWithGasPriceOracle.sol
index c4f697d9..88937ffd 100644
--- a/src/L1/rollup/IL1MessageQueueWithGasPriceOracle.sol
+++ b/src/L1/rollup/IL1MessageQueueWithGasPriceOracle.sol
@@ -4,6 +4,7 @@ pragma solidity ^0.8.24;
 
 import {IL1MessageQueueV1} from "./IL1MessageQueueV1.sol";
 
+/// @custom:deprecated This contract is no longer used in production.
 interface IL1MessageQueueWithGasPriceOracle is IL1MessageQueueV1 {
     /**********
      * Events *
diff --git a/src/L1/rollup/IL2GasPriceOracle.sol b/src/L1/rollup/IL2GasPriceOracle.sol
index 773c1c95..e7da38ec 100644
--- a/src/L1/rollup/IL2GasPriceOracle.sol
+++ b/src/L1/rollup/IL2GasPriceOracle.sol
@@ -2,6 +2,7 @@
 
 pragma solidity ^0.8.24;
 
+/// @custom:deprecated This contract is no longer used in production.
 interface IL2GasPriceOracle {
     /// @notice Return the latest known l2 base fee.
     function l2BaseFee() external view returns (uint256);
diff --git a/src/L1/rollup/L1MessageQueueV1.sol b/src/L1/rollup/L1MessageQueueV1.sol
index bc24be86..dc5d8ffb 100644
--- a/src/L1/rollup/L1MessageQueueV1.sol
+++ b/src/L1/rollup/L1MessageQueueV1.sol
@@ -17,6 +17,7 @@ import {AddressAliasHelper} from "../../libraries/common/AddressAliasHelper.sol"
 /// @title L1MessageQueue
 /// @notice This contract will hold all L1 to L2 messages.
 /// Each appended message is assigned with a unique and increasing `uint256` index.
+/// @custom:deprecated This contract is no longer used in production.
 contract L1MessageQueueV1 is OwnableUpgradeable, IL1MessageQueueV1 {
     using BitMapsUpgradeable for BitMapsUpgradeable.BitMap;
 
diff --git a/src/L1/rollup/L1MessageQueueV1WithGasPriceOracle.sol b/src/L1/rollup/L1MessageQueueV1WithGasPriceOracle.sol
index 40873d94..b84f2bd0 100644
--- a/src/L1/rollup/L1MessageQueueV1WithGasPriceOracle.sol
+++ b/src/L1/rollup/L1MessageQueueV1WithGasPriceOracle.sol
@@ -9,6 +9,7 @@ import {IL2GasPriceOracle} from "./IL2GasPriceOracle.sol";
 
 import {L1MessageQueueV1} from "./L1MessageQueueV1.sol";
 
+/// @custom:deprecated This contract is no longer used in production.
 contract L1MessageQueueV1WithGasPriceOracle is L1MessageQueueV1, IL1MessageQueueWithGasPriceOracle {
     /*************
      * Constants *
diff --git a/src/L1/rollup/L2GasPriceOracle.sol b/src/L1/rollup/L2GasPriceOracle.sol
index 4585621a..7fe65029 100644
--- a/src/L1/rollup/L2GasPriceOracle.sol
+++ b/src/L1/rollup/L2GasPriceOracle.sol
@@ -10,6 +10,7 @@ import {IL2GasPriceOracle} from "./IL2GasPriceOracle.sol";
 
 // solhint-disable reason-string
 
+/// @custom:deprecated This contract is no longer used in production.
 contract L2GasPriceOracle is OwnableUpgradeable, IL2GasPriceOracle {
     /**********
      * Events *
diff --git a/src/batch-bridge/L1BatchBridgeGateway.sol b/src/batch-bridge/L1BatchBridgeGateway.sol
index 6f1dcbb3..75b46b2a 100644
--- a/src/batch-bridge/L1BatchBridgeGateway.sol
+++ b/src/batch-bridge/L1BatchBridgeGateway.sol
@@ -16,6 +16,7 @@ import {BatchBridgeCodec} from "./BatchBridgeCodec.sol";
 import {L2BatchBridgeGateway} from "./L2BatchBridgeGateway.sol";
 
 /// @title L1BatchBridgeGateway
+/// @custom:deprecated This contract is no longer used in production.
 contract L1BatchBridgeGateway is AccessControlEnumerableUpgradeable, ReentrancyGuardUpgradeable {
     using SafeERC20Upgradeable for IERC20Upgradeable;
 
diff --git a/src/batch-bridge/L2BatchBridgeGateway.sol b/src/batch-bridge/L2BatchBridgeGateway.sol
index e069411a..4e01e68f 100644
--- a/src/batch-bridge/L2BatchBridgeGateway.sol
+++ b/src/batch-bridge/L2BatchBridgeGateway.sol
@@ -9,6 +9,7 @@ import {IL2ScrollMessenger} from "../L2/IL2ScrollMessenger.sol";
 import {BatchBridgeCodec} from "./BatchBridgeCodec.sol";
 
 /// @title L2BatchBridgeGateway
+/// @custom:deprecated This contract is no longer used in production.
 contract L2BatchBridgeGateway is AccessControlEnumerableUpgradeable {
     /**********
      * Events *
diff --git a/src/gas-swap/GasSwap.sol b/src/gas-swap/GasSwap.sol
deleted file mode 100644
index 61bea33c..00000000
--- a/src/gas-swap/GasSwap.sol
+++ /dev/null
@@ -1,201 +0,0 @@
-// SPDX-License-Identifier: MIT
-
-pragma solidity =0.8.24;
-
-import {Ownable} from "@openzeppelin/contracts/access/Ownable.sol";
-import {ERC2771Context} from "@openzeppelin/contracts/metatx/ERC2771Context.sol";
-import {ReentrancyGuard} from "@openzeppelin/contracts/security/ReentrancyGuard.sol";
-import {IERC20} from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
-import {SafeERC20} from "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
-import {IERC20Permit} from "@openzeppelin/contracts/token/ERC20/extensions/draft-IERC20Permit.sol";
-import {Context} from "@openzeppelin/contracts/utils/Context.sol";
-
-// solhint-disable no-empty-blocks
-
-contract GasSwap is ERC2771Context, Ownable, ReentrancyGuard {
-    using SafeERC20 for IERC20;
-    using SafeERC20 for IERC20Permit;
-
-    /**********
-     * Events *
-     **********/
-
-    /// @notice Emitted when the fee ratio is updated.
-    /// @param feeRatio The new fee ratio, multiplied by 1e18.
-    event UpdateFeeRatio(uint256 feeRatio);
-
-    /// @notice Emitted when the status of target is updated.
-    /// @param target The address of target contract.
-    /// @param status The status updated.
-    event UpdateApprovedTarget(address target, bool status);
-
-    /*************
-     * Constants *
-     *************/
-
-    /// @dev The fee precision.
-    uint256 private constant PRECISION = 1e18;
-
-    /***********
-     * Structs *
-     ***********/
-
-    struct PermitData {
-        // The address of token to spend.
-        address token;
-        // The amount of token to spend.
-        uint256 value;
-        // The deadline of the permit.
-        uint256 deadline;
-        // Below three are signatures.
-        uint8 v;
-        bytes32 r;
-        bytes32 s;
-    }
-
-    struct SwapData {
-        // The address of target contract to call.
-        address target;
-        // The calldata passed to target contract.
-        bytes data;
-        // The minimum amount of Ether should receive.
-        uint256 minOutput;
-    }
-
-    /*************
-     * Variables *
-     *************/
-
-    /// @notice Keep track whether an address is approved.
-    mapping(address => bool) public approvedTargets;
-
-    /// @notice The fee ratio charged for each swap, multiplied by 1e18.
-    uint256 public feeRatio;
-
-    /***************
-     * Constructor *
-     ***************/
-
-    constructor(address trustedForwarder) ERC2771Context(trustedForwarder) {}
-
-    /*****************************
-     * Public Mutating Functions *
-     *****************************/
-
-    receive() external payable {}
-
-    /// @notice Swap some token for ether.
-    /// @param _permit The permit data, see comments from `PermitData`.
-    /// @param _swap The swap data, see comments from `SwapData`.
-    function swap(PermitData memory _permit, SwapData memory _swap) external nonReentrant {
-        require(approvedTargets[_swap.target], "target not approved");
-        address _sender = _msgSender();
-
-        // do permit
-        IERC20Permit(_permit.token).safePermit(
-            _sender,
-            address(this),
-            _permit.value,
-            _permit.deadline,
-            _permit.v,
-            _permit.r,
-            _permit.s
-        );
-
-        // record token balance in this contract
-        uint256 _balance = IERC20(_permit.token).balanceOf(address(this));
-
-        // transfer token
-        IERC20(_permit.token).safeTransferFrom(_sender, address(this), _permit.value);
-
-        // approve
-        IERC20(_permit.token).safeApprove(_swap.target, 0);
-        IERC20(_permit.token).safeApprove(_swap.target, _permit.value);
-
-        // do swap
-        uint256 _outputTokenAmount = address(this).balance;
-        // solhint-disable-next-line avoid-low-level-calls
-        (bool _success, bytes memory _res) = _swap.target.call(_swap.data);
-        require(_success, string(concat(bytes("swap failed: "), bytes(getRevertMsg(_res)))));
-        _outputTokenAmount = address(this).balance - _outputTokenAmount;
-
-        // take fee
-        uint256 _fee = (_outputTokenAmount * feeRatio) / PRECISION;
-        _outputTokenAmount = _outputTokenAmount - _fee;
-        require(_outputTokenAmount >= _swap.minOutput, "insufficient output amount");
-
-        // transfer ETH to sender
-        (_success, ) = _sender.call{value: _outputTokenAmount}("");
-        require(_success, "transfer ETH failed");
-
-        // refund rest token
-        uint256 _dust = IERC20(_permit.token).balanceOf(address(this)) - _balance;
-        if (_dust > 0) {
-            IERC20(_permit.token).safeTransfer(_sender, _dust);
-        }
-    }
-
-    /************************
-     * Restricted Functions *
-     ************************/
-
-    /// @notice Withdraw stucked tokens.
-    /// @param _token The address of token to withdraw. Use `address(0)` if you want to withdraw Ether.
-    /// @param _amount The amount of token to withdraw.
-    function withdraw(address _token, uint256 _amount) external onlyOwner {
-        if (_token == address(0)) {
-            (bool success, ) = _msgSender().call{value: _amount}("");
-            require(success, "ETH transfer failed");
-        } else {
-            IERC20(_token).safeTransfer(_msgSender(), _amount);
-        }
-    }
-
-    /// @notice Update the fee ratio.
-    /// @param _feeRatio The new fee ratio.
-    function updateFeeRatio(uint256 _feeRatio) external onlyOwner {
-        feeRatio = _feeRatio;
-
-        emit UpdateFeeRatio(_feeRatio);
-    }
-
-    /// @notice Update the status of a target address.
-    /// @param _target The address of target to update.
-    /// @param _status The new status.
-    function updateApprovedTarget(address _target, bool _status) external onlyOwner {
-        approvedTargets[_target] = _status;
-
-        emit UpdateApprovedTarget(_target, _status);
-    }
-
-    /**********************
-     * Internal Functions *
-     **********************/
-
-    /// @inheritdoc Context
-    function _msgData() internal view virtual override(Context, ERC2771Context) returns (bytes calldata) {
-        return ERC2771Context._msgData();
-    }
-
-    /// @inheritdoc Context
-    function _msgSender() internal view virtual override(Context, ERC2771Context) returns (address) {
-        return ERC2771Context._msgSender();
-    }
-
-    /// @dev Internal function to concat two bytes array.
-    function concat(bytes memory a, bytes memory b) internal pure returns (bytes memory) {
-        return abi.encodePacked(a, b);
-    }
-
-    /// @dev Internal function decode revert message from return data.
-    function getRevertMsg(bytes memory _returnData) internal pure returns (string memory) {
-        if (_returnData.length < 68) return "Transaction reverted silently";
-
-        // solhint-disable-next-line no-inline-assembly
-        assembly {
-            _returnData := add(_returnData, 0x04)
-        }
-
-        return abi.decode(_returnData, (string));
-    }
-}
diff --git a/src/libraries/callbacks/IMessageDropCallback.sol b/src/libraries/callbacks/IMessageDropCallback.sol
deleted file mode 100644
index e23f3cda..00000000
--- a/src/libraries/callbacks/IMessageDropCallback.sol
+++ /dev/null
@@ -1,7 +0,0 @@
-// SPDX-License-Identifier: MIT
-
-pragma solidity ^0.8.24;
-
-interface IMessageDropCallback {
-    function onDropMessage(bytes memory message) external payable;
-}
diff --git a/src/libraries/gateway/ScrollGatewayBase.sol b/src/libraries/gateway/ScrollGatewayBase.sol
index 4bc49ebc..59aa65d1 100644
--- a/src/libraries/gateway/ScrollGatewayBase.sol
+++ b/src/libraries/gateway/ScrollGatewayBase.sol
@@ -9,7 +9,6 @@ import {IScrollGateway} from "./IScrollGateway.sol";
 import {IScrollMessenger} from "../IScrollMessenger.sol";
 import {IScrollGatewayCallback} from "../callbacks/IScrollGatewayCallback.sol";
 import {ScrollConstants} from "../constants/ScrollConstants.sol";
-import {ITokenRateLimiter} from "../../rate-limiter/ITokenRateLimiter.sol";
 
 /// @title ScrollGatewayBase
 /// @notice The `ScrollGatewayBase` is a base contract for gateway contracts used in both in L1 and L2.
diff --git a/src/misc/ERC2771Forwarder.sol b/src/misc/ERC2771Forwarder.sol
deleted file mode 100644
index 8e1b4d69..00000000
--- a/src/misc/ERC2771Forwarder.sol
+++ /dev/null
@@ -1,391 +0,0 @@
-// SPDX-License-Identifier: MIT
-
-// @note This file is directly copied from OpenZeppelin's master branch:
-// https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/metatx/ERC2771Forwarder.sol
-// Modifications are made to make it compatible with solidity 0.8.16.
-
-pragma solidity =0.8.24;
-
-import {ERC2771Context} from "@openzeppelin/contracts/metatx/ERC2771Context.sol";
-import {ECDSA} from "@openzeppelin/contracts/utils/cryptography/ECDSA.sol";
-import {EIP712} from "@openzeppelin/contracts/utils/cryptography/EIP712.sol";
-import {Nonces} from "./Nonces.sol";
-import {Address} from "@openzeppelin/contracts/utils/Address.sol";
-
-/**
- * @dev A forwarder compatible with ERC2771 contracts. See {ERC2771Context}.
- *
- * This forwarder operates on forward requests that include:
- *
- * * `from`: An address to operate on behalf of. It is required to be equal to the request signer.
- * * `to`: The address that should be called.
- * * `value`: The amount of native token to attach with the requested call.
- * * `gas`: The amount of gas limit that will be forwarded with the requested call.
- * * `nonce`: A unique transaction ordering identifier to avoid replayability and request invalidation.
- * * `deadline`: A timestamp after which the request is not executable anymore.
- * * `data`: Encoded `msg.data` to send with the requested call.
- *
- * Relayers are able to submit batches if they are processing a high volume of requests. With high
- * throughput, relayers may run into limitations of the chain such as limits on the number of
- * transactions in the mempool. In these cases the recommendation is to distribute the load among
- * multiple accounts.
- *
- * NOTE: Batching requests includes an optional refund for unused `msg.value` that is achieved by
- * performing a call with empty calldata. While this is within the bounds of ERC-2771 compliance,
- * if the refund receiver happens to consider the forwarder a trusted forwarder, it MUST properly
- * handle `msg.data.length == 0`. `ERC2771Context` in OpenZeppelin Contracts versions prior to 4.9.3
- * do not handle this properly.
- *
- * ==== Security Considerations
- *
- * If a relayer submits a forward request, it should be willing to pay up to 100% of the gas amount
- * specified in the request. This contract does not implement any kind of retribution for this gas,
- * and it is assumed that there is an out of band incentive for relayers to pay for execution on
- * behalf of signers. Often, the relayer is operated by a project that will consider it a user
- * acquisition cost.
- *
- * By offering to pay for gas, relayers are at risk of having that gas used by an attacker toward
- * some other purpose that is not aligned with the expected out of band incentives. If you operate a
- * relayer, consider whitelisting target contracts and function selectors. When relaying ERC-721 or
- * ERC-1155 transfers specifically, consider rejecting the use of the `data` field, since it can be
- * used to execute arbitrary code.
- */
-contract ERC2771Forwarder is EIP712, Nonces {
-    using ECDSA for bytes32;
-
-    struct ForwardRequestData {
-        address from;
-        address to;
-        uint256 value;
-        uint256 gas;
-        uint48 deadline;
-        bytes data;
-        bytes signature;
-    }
-
-    bytes32 internal constant _FORWARD_REQUEST_TYPEHASH =
-        keccak256(
-            "ForwardRequest(address from,address to,uint256 value,uint256 gas,uint256 nonce,uint48 deadline,bytes data)"
-        );
-
-    /**
-     * @dev Emitted when a `ForwardRequest` is executed.
-     *
-     * NOTE: An unsuccessful forward request could be due to an invalid signature, an expired deadline,
-     * or simply a revert in the requested call. The contract guarantees that the relayer is not able to force
-     * the requested call to run out of gas.
-     */
-    event ExecutedForwardRequest(address indexed signer, uint256 nonce, bool success);
-
-    /**
-     * @dev The request `from` doesn't match with the recovered `signer`.
-     */
-    error ERC2771ForwarderInvalidSigner(address signer, address from);
-
-    /**
-     * @dev The `requestedValue` doesn't match with the available `msgValue`.
-     */
-    error ERC2771ForwarderMismatchedValue(uint256 requestedValue, uint256 msgValue);
-
-    /**
-     * @dev The request `deadline` has expired.
-     */
-    error ERC2771ForwarderExpiredRequest(uint48 deadline);
-
-    /**
-     * @dev The request target doesn't trust the `forwarder`.
-     */
-    error ERC2771UntrustfulTarget(address target, address forwarder);
-
-    /**
-     * @dev A call to an address target failed. The target may have reverted.
-     */
-    error FailedInnerCall();
-
-    /**
-     * @dev See {EIP712-constructor}.
-     */
-    constructor(string memory name) EIP712(name, "1") {}
-
-    /**
-     * @dev Returns `true` if a request is valid for a provided `signature` at the current block timestamp.
-     *
-     * A transaction is considered valid when the target trusts this forwarder, the request hasn't expired
-     * (deadline is not met), and the signer matches the `from` parameter of the signed request.
-     *
-     * NOTE: A request may return false here but it won't cause {executeBatch} to revert if a refund
-     * receiver is provided.
-     */
-    function verify(ForwardRequestData calldata request) public view virtual returns (bool) {
-        (bool isTrustedForwarder, bool active, bool signerMatch, ) = _validate(request);
-        return isTrustedForwarder && active && signerMatch;
-    }
-
-    /**
-     * @dev Executes a `request` on behalf of `signature`'s signer using the ERC-2771 protocol. The gas
-     * provided to the requested call may not be exactly the amount requested, but the call will not run
-     * out of gas. Will revert if the request is invalid or the call reverts, in this case the nonce is not consumed.
-     *
-     * Requirements:
-     *
-     * - The request value should be equal to the provided `msg.value`.
-     * - The request should be valid according to {verify}.
-     */
-    function execute(ForwardRequestData calldata request) public payable virtual {
-        // We make sure that msg.value and request.value match exactly.
-        // If the request is invalid or the call reverts, this whole function
-        // will revert, ensuring value isn't stuck.
-        if (msg.value != request.value) {
-            revert ERC2771ForwarderMismatchedValue(request.value, msg.value);
-        }
-
-        if (!_execute(request, true)) {
-            revert FailedInnerCall();
-        }
-    }
-
-    /**
-     * @dev Batch version of {execute} with optional refunding and atomic execution.
-     *
-     * In case a batch contains at least one invalid request (see {verify}), the
-     * request will be skipped and the `refundReceiver` parameter will receive back the
-     * unused requested value at the end of the execution. This is done to prevent reverting
-     * the entire batch when a request is invalid or has already been submitted.
-     *
-     * If the `refundReceiver` is the `address(0)`, this function will revert when at least
-     * one of the requests was not valid instead of skipping it. This could be useful if
-     * a batch is required to get executed atomically (at least at the top-level). For example,
-     * refunding (and thus atomicity) can be opt-out if the relayer is using a service that avoids
-     * including reverted transactions.
-     *
-     * Requirements:
-     *
-     * - The sum of the requests' values should be equal to the provided `msg.value`.
-     * - All of the requests should be valid (see {verify}) when `refundReceiver` is the zero address.
-     *
-     * NOTE: Setting a zero `refundReceiver` guarantees an all-or-nothing requests execution only for
-     * the first-level forwarded calls. In case a forwarded request calls to a contract with another
-     * subcall, the second-level call may revert without the top-level call reverting.
-     */
-    function executeBatch(ForwardRequestData[] calldata requests, address payable refundReceiver)
-        public
-        payable
-        virtual
-    {
-        bool atomic = refundReceiver == address(0);
-
-        uint256 requestsValue;
-        uint256 refundValue;
-
-        for (uint256 i; i < requests.length; ++i) {
-            requestsValue += requests[i].value;
-            bool success = _execute(requests[i], atomic);
-            if (!success) {
-                refundValue += requests[i].value;
-            }
-        }
-
-        // The batch should revert if there's a mismatched msg.value provided
-        // to avoid request value tampering
-        if (requestsValue != msg.value) {
-            revert ERC2771ForwarderMismatchedValue(requestsValue, msg.value);
-        }
-
-        // Some requests with value were invalid (possibly due to frontrunning).
-        // To avoid leaving ETH in the contract this value is refunded.
-        if (refundValue != 0) {
-            // We know refundReceiver != address(0) && requestsValue == msg.value
-            // meaning we can ensure refundValue is not taken from the original contract's balance
-            // and refundReceiver is a known account.
-            Address.sendValue(refundReceiver, refundValue);
-        }
-    }
-
-    /**
-     * @dev Validates if the provided request can be executed at current block timestamp with
-     * the given `request.signature` on behalf of `request.signer`.
-     */
-    function _validate(ForwardRequestData calldata request)
-        internal
-        view
-        virtual
-        returns (
-            bool isTrustedForwarder,
-            bool active,
-            bool signerMatch,
-            address signer
-        )
-    {
-        (bool isValid, address recovered) = _recoverForwardRequestSigner(request);
-
-        return (
-            _isTrustedByTarget(request.to),
-            request.deadline >= block.timestamp,
-            isValid && recovered == request.from,
-            recovered
-        );
-    }
-
-    /**
-     * @dev Returns a tuple with the recovered the signer of an EIP712 forward request message hash
-     * and a boolean indicating if the signature is valid.
-     *
-     * NOTE: The signature is considered valid if {ECDSA-tryRecover} indicates no recover error for it.
-     */
-    function _recoverForwardRequestSigner(ForwardRequestData calldata request)
-        internal
-        view
-        virtual
-        returns (bool, address)
-    {
-        (address recovered, ECDSA.RecoverError err) = _hashTypedDataV4(
-            keccak256(
-                abi.encode(
-                    _FORWARD_REQUEST_TYPEHASH,
-                    request.from,
-                    request.to,
-                    request.value,
-                    request.gas,
-                    nonces(request.from),
-                    request.deadline,
-                    keccak256(request.data)
-                )
-            )
-        ).tryRecover(request.signature);
-
-        return (err == ECDSA.RecoverError.NoError, recovered);
-    }
-
-    /**
-     * @dev Validates and executes a signed request returning the request call `success` value.
-     *
-     * Internal function without msg.value validation.
-     *
-     * Requirements:
-     *
-     * - The caller must have provided enough gas to forward with the call.
-     * - The request must be valid (see {verify}) if the `requireValidRequest` is true.
-     *
-     * Emits an {ExecutedForwardRequest} event.
-     *
-     * IMPORTANT: Using this function doesn't check that all the `msg.value` was sent, potentially
-     * leaving value stuck in the contract.
-     */
-    function _execute(ForwardRequestData calldata request, bool requireValidRequest)
-        internal
-        virtual
-        returns (bool success)
-    {
-        (bool isTrustedForwarder, bool active, bool signerMatch, address signer) = _validate(request);
-
-        // Need to explicitly specify if a revert is required since non-reverting is default for
-        // batches and reversion is opt-in since it could be useful in some scenarios
-        if (requireValidRequest) {
-            if (!isTrustedForwarder) {
-                revert ERC2771UntrustfulTarget(request.to, address(this));
-            }
-
-            if (!active) {
-                revert ERC2771ForwarderExpiredRequest(request.deadline);
-            }
-
-            if (!signerMatch) {
-                revert ERC2771ForwarderInvalidSigner(signer, request.from);
-            }
-        }
-
-        // Ignore an invalid request because requireValidRequest = false
-        if (isTrustedForwarder && signerMatch && active) {
-            // Nonce should be used before the call to prevent reusing by reentrancy
-            uint256 currentNonce = _useNonce(signer);
-
-            uint256 reqGas = request.gas;
-            address to = request.to;
-            uint256 value = request.value;
-            bytes memory data = abi.encodePacked(request.data, request.from);
-
-            uint256 gasLeft;
-
-            assembly {
-                success := call(reqGas, to, value, add(data, 0x20), mload(data), 0, 0)
-                gasLeft := gas()
-            }
-
-            _checkForwardedGas(gasLeft, request);
-
-            emit ExecutedForwardRequest(signer, currentNonce, success);
-        }
-    }
-
-    /**
-     * @dev Returns whether the target trusts this forwarder.
-     *
-     * This function performs a static call to the target contract calling the
-     * {ERC2771Context-isTrustedForwarder} function.
-     */
-    function _isTrustedByTarget(address target) private view returns (bool) {
-        bytes memory encodedParams = abi.encodeCall(ERC2771Context.isTrustedForwarder, (address(this)));
-
-        bool success;
-        uint256 returnSize;
-        uint256 returnValue;
-        /// @solidity memory-safe-assembly
-        assembly {
-            // Perform the staticcal and save the result in the scratch space.
-            // | Location  | Content  | Content (Hex)                                                      |
-            // |-----------|----------|--------------------------------------------------------------------|
-            // |           |          |                                                           result ↓ |
-            // | 0x00:0x1F | selector | 0x0000000000000000000000000000000000000000000000000000000000000001 |
-            success := staticcall(gas(), target, add(encodedParams, 0x20), mload(encodedParams), 0, 0x20)
-            returnSize := returndatasize()
-            returnValue := mload(0)
-        }
-
-        return success && returnSize >= 0x20 && returnValue > 0;
-    }
-
-    /**
-     * @dev Checks if the requested gas was correctly forwarded to the callee.
-     *
-     * As a consequence of https://eips.ethereum.org/EIPS/eip-150[EIP-150]:
-     * - At most `gasleft() - floor(gasleft() / 64)` is forwarded to the callee.
-     * - At least `floor(gasleft() / 64)` is kept in the caller.
-     *
-     * It reverts consuming all the available gas if the forwarded gas is not the requested gas.
-     *
-     * IMPORTANT: The `gasLeft` parameter should be measured exactly at the end of the forwarded call.
-     * Any gas consumed in between will make room for bypassing this check.
-     */
-    function _checkForwardedGas(uint256 gasLeft, ForwardRequestData calldata request) private pure {
-        // To avoid insufficient gas griefing attacks, as referenced in https://ronan.eth.limo/blog/ethereum-gas-dangers/
-        //
-        // A malicious relayer can attempt to shrink the gas forwarded so that the underlying call reverts out-of-gas
-        // but the forwarding itself still succeeds. In order to make sure that the subcall received sufficient gas,
-        // we will inspect gasleft() after the forwarding.
-        //
-        // Let X be the gas available before the subcall, such that the subcall gets at most X * 63 / 64.
-        // We can't know X after CALL dynamic costs, but we want it to be such that X * 63 / 64 >= req.gas.
-        // Let Y be the gas used in the subcall. gasleft() measured immediately after the subcall will be gasleft() = X - Y.
-        // If the subcall ran out of gas, then Y = X * 63 / 64 and gasleft() = X - Y = X / 64.
-        // Under this assumption req.gas / 63 > gasleft() is true is true if and only if
-        // req.gas / 63 > X / 64, or equivalently req.gas > X * 63 / 64.
-        // This means that if the subcall runs out of gas we are able to detect that insufficient gas was passed.
-        //
-        // We will now also see that req.gas / 63 > gasleft() implies that req.gas >= X * 63 / 64.
-        // The contract guarantees Y <= req.gas, thus gasleft() = X - Y >= X - req.gas.
-        // -    req.gas / 63 > gasleft()
-        // -    req.gas / 63 >= X - req.gas
-        // -    req.gas >= X * 63 / 64
-        // In other words if req.gas < X * 63 / 64 then req.gas / 63 <= gasleft(), thus if the relayer behaves honestly
-        // the forwarding does not revert.
-        if (gasLeft < request.gas / 63) {
-            // We explicitly trigger invalid opcode to consume all gas and bubble-up the effects, since
-            // neither revert or assert consume all gas since Solidity 0.8.20
-            // https://docs.soliditylang.org/en/v0.8.20/control-structures.html#panic-via-assert-and-error-via-require
-            /// @solidity memory-safe-assembly
-            assembly {
-                invalid()
-            }
-        }
-    }
-}
diff --git a/src/misc/Nonces.sol b/src/misc/Nonces.sol
deleted file mode 100644
index 7c761498..00000000
--- a/src/misc/Nonces.sol
+++ /dev/null
@@ -1,51 +0,0 @@
-// SPDX-License-Identifier: MIT
-
-// @note This file is directly copied from OpenZeppelin's master branch:
-// https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/utils/Nonces.sol
-// Modifications are made to make it compatible with solidity 0.8.16.
-
-pragma solidity ^0.8.24;
-
-/**
- * @dev Provides tracking nonces for addresses. Nonces will only increment.
- */
-abstract contract Nonces {
-    /**
-     * @dev The nonce used for an `account` is not the expected current nonce.
-     */
-    error InvalidAccountNonce(address account, uint256 currentNonce);
-
-    mapping(address => uint256) private _nonces;
-
-    /**
-     * @dev Returns an the next unused nonce for an address.
-     */
-    function nonces(address owner) public view virtual returns (uint256) {
-        return _nonces[owner];
-    }
-
-    /**
-     * @dev Consumes a nonce.
-     *
-     * Returns the current value and increments nonce.
-     */
-    function _useNonce(address owner) internal virtual returns (uint256) {
-        // For each account, the nonce has an initial value of 0, can only be incremented by one, and cannot be
-        // decremented or reset. This guarantees that the nonce never overflows.
-        unchecked {
-            // It is important to do x++ and not ++x here.
-            return _nonces[owner]++;
-        }
-    }
-
-    /**
-     * @dev Same as {_useNonce} but checking that `nonce` is the next valid for `owner`.
-     */
-    function _useCheckedNonce(address owner, uint256 nonce) internal virtual returns (uint256) {
-        uint256 current = _useNonce(owner);
-        if (nonce != current) {
-            revert InvalidAccountNonce(owner, current);
-        }
-        return current;
-    }
-}
diff --git a/src/rate-limiter/ETHRateLimiter.sol b/src/rate-limiter/ETHRateLimiter.sol
deleted file mode 100644
index 31ba904c..00000000
--- a/src/rate-limiter/ETHRateLimiter.sol
+++ /dev/null
@@ -1,122 +0,0 @@
-// SPDX-License-Identifier: MIT
-
-pragma solidity =0.8.24;
-
-import {Ownable} from "@openzeppelin/contracts/access/Ownable.sol";
-import {SafeCast} from "@openzeppelin/contracts/utils/math/SafeCast.sol";
-
-import {IETHRateLimiter} from "./IETHRateLimiter.sol";
-
-// solhint-disable func-name-mixedcase
-// solhint-disable not-rely-on-time
-
-contract ETHRateLimiter is Ownable, IETHRateLimiter {
-    /***********
-     * Structs *
-     ***********/
-
-    struct ETHAmount {
-        // The timestamp when the amount is updated.
-        uint48 lastUpdateTs;
-        // The ETH limit in wei.
-        uint104 limit;
-        // The amount of ETH in current period.
-        uint104 amount;
-    }
-
-    /*************
-     * Constants *
-     *************/
-
-    /// @notice The period length in seconds.
-    /// @dev The time frame for the `k`-th period is `[periodDuration * k, periodDuration * (k + 1))`.
-    uint256 public immutable periodDuration;
-
-    /// @notice The address of ETH spender.
-    address public immutable spender;
-
-    /*************
-     * Variables *
-     *************/
-
-    /// @notice The ETH amount used in current period.
-    ETHAmount public currentPeriod;
-
-    /***************
-     * Constructor *
-     ***************/
-
-    constructor(
-        uint256 _periodDuration,
-        address _spender,
-        uint104 _totalLimit
-    ) {
-        if (_periodDuration == 0) {
-            revert PeriodIsZero();
-        }
-
-        periodDuration = _periodDuration;
-        spender = _spender;
-
-        _updateTotalLimit(_totalLimit);
-    }
-
-    /*****************************
-     * Public Mutating Functions *
-     *****************************/
-
-    /// @inheritdoc IETHRateLimiter
-    function addUsedAmount(uint256 _amount) external override {
-        if (_msgSender() != spender) {
-            revert CallerNotSpender();
-        }
-        if (_amount == 0) return;
-
-        uint256 _currentPeriodStart = (block.timestamp / periodDuration) * periodDuration;
-
-        // check total limit
-        uint256 _currentTotalAmount;
-        ETHAmount memory _currentPeriod = currentPeriod;
-
-        if (uint256(_currentPeriod.lastUpdateTs) < _currentPeriodStart) {
-            _currentTotalAmount = _amount;
-        } else {
-            _currentTotalAmount = _currentPeriod.amount + _amount;
-        }
-        if (_currentTotalAmount > _currentPeriod.limit) {
-            revert ExceedTotalLimit();
-        }
-
-        _currentPeriod.lastUpdateTs = uint48(block.timestamp);
-        _currentPeriod.amount = SafeCast.toUint104(_currentTotalAmount);
-
-        currentPeriod = _currentPeriod;
-    }
-
-    /************************
-     * Restricted Functions *
-     ************************/
-
-    /// @notice Update the total ETH amount limit.
-    /// @param _newTotalLimit The new total limit.
-    function updateTotalLimit(uint104 _newTotalLimit) external onlyOwner {
-        _updateTotalLimit(_newTotalLimit);
-    }
-
-    /**********************
-     * Internal Functions *
-     **********************/
-
-    /// @dev Internal function to update the total token amount limit.
-    /// @param _newTotalLimit The new total limit.
-    function _updateTotalLimit(uint104 _newTotalLimit) private {
-        if (_newTotalLimit == 0) {
-            revert TotalLimitIsZero();
-        }
-
-        uint256 _oldTotalLimit = currentPeriod.limit;
-        currentPeriod.limit = _newTotalLimit;
-
-        emit UpdateTotalLimit(_oldTotalLimit, _newTotalLimit);
-    }
-}
diff --git a/src/rate-limiter/IETHRateLimiter.sol b/src/rate-limiter/IETHRateLimiter.sol
deleted file mode 100644
index 43db682e..00000000
--- a/src/rate-limiter/IETHRateLimiter.sol
+++ /dev/null
@@ -1,38 +0,0 @@
-// SPDX-License-Identifier: MIT
-
-pragma solidity ^0.8.24;
-
-interface IETHRateLimiter {
-    /**********
-     * Events *
-     **********/
-
-    /// @notice Emitted when the total limit is updated.
-    /// @param oldTotalLimit The previous value of total limit before updating.
-    /// @param newTotalLimit The current value of total limit after updating.
-    event UpdateTotalLimit(uint256 oldTotalLimit, uint256 newTotalLimit);
-
-    /**********
-     * Errors *
-     **********/
-
-    /// @dev Thrown when the `periodDuration` is initialized to zero.
-    error PeriodIsZero();
-
-    /// @dev Thrown when the `totalAmount` is initialized to zero.
-    error TotalLimitIsZero();
-
-    /// @dev Thrown when an amount breaches the total limit in the period.
-    error ExceedTotalLimit();
-
-    /// @dev Thrown when the call is not spender.
-    error CallerNotSpender();
-
-    /*****************************
-     * Public Mutating Functions *
-     *****************************/
-
-    /// @notice Request some ETH usage for `sender`.
-    /// @param _amount The amount of ETH to use.
-    function addUsedAmount(uint256 _amount) external;
-}
diff --git a/src/rate-limiter/ITokenRateLimiter.sol b/src/rate-limiter/ITokenRateLimiter.sol
deleted file mode 100644
index 050680ef..00000000
--- a/src/rate-limiter/ITokenRateLimiter.sol
+++ /dev/null
@@ -1,38 +0,0 @@
-// SPDX-License-Identifier: MIT
-
-pragma solidity ^0.8.24;
-
-interface ITokenRateLimiter {
-    /**********
-     * Events *
-     **********/
-
-    /// @notice Emitted when the total limit is updated.
-    /// @param oldTotalLimit The previous value of total limit before updating.
-    /// @param newTotalLimit The current value of total limit after updating.
-    event UpdateTotalLimit(address indexed token, uint256 oldTotalLimit, uint256 newTotalLimit);
-
-    /**********
-     * Errors *
-     **********/
-
-    /// @dev Thrown when the `periodDuration` is initialized to zero.
-    error PeriodIsZero();
-
-    /// @dev Thrown when the `totalAmount` is initialized to zero.
-    /// @param token The address of the token.
-    error TotalLimitIsZero(address token);
-
-    /// @dev Thrown when an amount breaches the total limit in the period.
-    /// @param token The address of the token.
-    error ExceedTotalLimit(address token);
-
-    /*****************************
-     * Public Mutating Functions *
-     *****************************/
-
-    /// @notice Request some token usage for `sender`.
-    /// @param token The address of the token.
-    /// @param amount The amount of token to use.
-    function addUsedAmount(address token, uint256 amount) external;
-}
diff --git a/src/rate-limiter/TokenRateLimiter.sol b/src/rate-limiter/TokenRateLimiter.sol
deleted file mode 100644
index dab08e8a..00000000
--- a/src/rate-limiter/TokenRateLimiter.sol
+++ /dev/null
@@ -1,106 +0,0 @@
-// SPDX-License-Identifier: MIT
-
-pragma solidity =0.8.24;
-
-import {AccessControlEnumerable} from "@openzeppelin/contracts/access/AccessControlEnumerable.sol";
-import {SafeCast} from "@openzeppelin/contracts/utils/math/SafeCast.sol";
-
-import {ITokenRateLimiter} from "./ITokenRateLimiter.sol";
-
-// solhint-disable func-name-mixedcase
-// solhint-disable not-rely-on-time
-
-contract TokenRateLimiter is AccessControlEnumerable, ITokenRateLimiter {
-    /***********
-     * Structs *
-     ***********/
-
-    struct TokenAmount {
-        // The timestamp when the amount is updated.
-        uint48 lastUpdateTs;
-        // The token limit.
-        uint104 limit;
-        // The amount of token in current period.
-        uint104 amount;
-    }
-
-    /*************
-     * Constants *
-     *************/
-
-    /// @notice The role for token spender.
-    bytes32 public constant TOKEN_SPENDER_ROLE = keccak256("TOKEN_SPENDER_ROLE");
-
-    /// @notice The period length in seconds.
-    /// @dev The time frame for the `k`-th period is `[periodDuration * k, periodDuration * (k + 1))`.
-    uint256 public immutable periodDuration;
-
-    /*************
-     * Variables *
-     *************/
-
-    /// @notice Mapping from token address to the total amounts used in current period and total token amount limit.
-    mapping(address => TokenAmount) public currentPeriod;
-
-    /// @dev The storage slots for future usage.
-    uint256[49] private __gap;
-
-    /***************
-     * Constructor *
-     ***************/
-
-    constructor(uint256 _periodDuration) {
-        if (_periodDuration == 0) {
-            revert PeriodIsZero();
-        }
-
-        _grantRole(DEFAULT_ADMIN_ROLE, _msgSender());
-
-        periodDuration = _periodDuration;
-    }
-
-    /*****************************
-     * Public Mutating Functions *
-     *****************************/
-
-    /// @inheritdoc ITokenRateLimiter
-    function addUsedAmount(address _token, uint256 _amount) external override onlyRole(TOKEN_SPENDER_ROLE) {
-        if (_amount == 0) return;
-
-        uint256 _currentPeriodStart = (block.timestamp / periodDuration) * periodDuration;
-
-        // check total limit, `0` means no limit at all.
-        uint256 _currentTotalAmount;
-        TokenAmount memory _currentPeriod = currentPeriod[_token];
-        if (uint256(_currentPeriod.lastUpdateTs) < _currentPeriodStart) {
-            _currentTotalAmount = _amount;
-        } else {
-            _currentTotalAmount = _currentPeriod.amount + _amount;
-        }
-        if (_currentPeriod.limit != 0 && _currentTotalAmount > _currentPeriod.limit) {
-            revert ExceedTotalLimit(_token);
-        }
-
-        _currentPeriod.lastUpdateTs = uint48(block.timestamp);
-        _currentPeriod.amount = SafeCast.toUint104(_currentTotalAmount);
-
-        currentPeriod[_token] = _currentPeriod;
-    }
-
-    /************************
-     * Restricted Functions *
-     ************************/
-
-    /// @notice Update the total token amount limit.
-    /// @param _newTotalLimit The new total limit.
-    function updateTotalLimit(address _token, uint104 _newTotalLimit) external onlyRole(DEFAULT_ADMIN_ROLE) {
-        if (_newTotalLimit == 0) {
-            revert TotalLimitIsZero(_token);
-        }
-
-        uint256 _oldTotalLimit = currentPeriod[_token].limit;
-        currentPeriod[_token].limit = _newTotalLimit;
-
-        emit UpdateTotalLimit(_token, _oldTotalLimit, _newTotalLimit);
-    }
-}
diff --git a/src/test/ETHRateLimiter.t.sol b/src/test/ETHRateLimiter.t.sol
deleted file mode 100644
index 31c53725..00000000
--- a/src/test/ETHRateLimiter.t.sol
+++ /dev/null
@@ -1,75 +0,0 @@
-// SPDX-License-Identifier: MIT
-
-pragma solidity =0.8.24;
-
-import {DSTestPlus} from "solmate/test/utils/DSTestPlus.sol";
-
-import {ETHRateLimiter} from "../rate-limiter/ETHRateLimiter.sol";
-import {IETHRateLimiter} from "../rate-limiter/IETHRateLimiter.sol";
-
-contract ETHRateLimiterTest is DSTestPlus {
-    event UpdateTotalLimit(uint256 oldTotalLimit, uint256 newTotalLimit);
-
-    ETHRateLimiter private limiter;
-
-    function setUp() public {
-        hevm.warp(86400);
-        limiter = new ETHRateLimiter(86400, address(this), 100 ether);
-    }
-
-    function testUpdateTotalLimit(uint104 _newTotalLimit) external {
-        hevm.assume(_newTotalLimit > 0);
-
-        // not owner, revert
-        hevm.startPrank(address(1));
-        hevm.expectRevert("Ownable: caller is not the owner");
-        limiter.updateTotalLimit(_newTotalLimit);
-        hevm.stopPrank();
-
-        // zero revert
-        hevm.expectRevert(IETHRateLimiter.TotalLimitIsZero.selector);
-        limiter.updateTotalLimit(0);
-
-        // success
-        hevm.expectEmit(false, false, false, true);
-        emit UpdateTotalLimit(100 ether, _newTotalLimit);
-        limiter.updateTotalLimit(_newTotalLimit);
-        (, uint104 _totalLimit, ) = limiter.currentPeriod();
-        assertEq(_totalLimit, _newTotalLimit);
-    }
-
-    function testAddUsedAmount() external {
-        // non-spender, revert
-        hevm.startPrank(address(1));
-        hevm.expectRevert(IETHRateLimiter.CallerNotSpender.selector);
-        limiter.addUsedAmount(0);
-        hevm.stopPrank();
-
-        // exceed total limit on first call
-        hevm.expectRevert(IETHRateLimiter.ExceedTotalLimit.selector);
-        limiter.addUsedAmount(100 ether + 1);
-        _checkTotalCurrentPeriodAmountAmount(0);
-
-        // exceed total limit on second call
-        limiter.addUsedAmount(50 ether);
-        _checkTotalCurrentPeriodAmountAmount(50 ether);
-        hevm.expectRevert(IETHRateLimiter.ExceedTotalLimit.selector);
-        limiter.addUsedAmount(50 ether + 1);
-        _checkTotalCurrentPeriodAmountAmount(50 ether);
-
-        // one period passed
-        hevm.warp(86400 * 2);
-        limiter.addUsedAmount(1 ether);
-        _checkTotalCurrentPeriodAmountAmount(1 ether);
-
-        // exceed
-        hevm.expectRevert(IETHRateLimiter.ExceedTotalLimit.selector);
-        limiter.addUsedAmount(99 ether + 1);
-        _checkTotalCurrentPeriodAmountAmount(1 ether);
-    }
-
-    function _checkTotalCurrentPeriodAmountAmount(uint256 expected) internal {
-        (, , uint256 totalAmount) = limiter.currentPeriod();
-        assertEq(totalAmount, expected);
-    }
-}
diff --git a/src/test/L1CustomERC20Gateway.t.sol b/src/test/L1CustomERC20Gateway.t.sol
index 98e0a75b..1443061d 100644
--- a/src/test/L1CustomERC20Gateway.t.sol
+++ b/src/test/L1CustomERC20Gateway.t.sol
@@ -130,94 +130,6 @@ contract L1CustomERC20GatewayTest is L1GatewayTestBase {
         _depositERC20WithRecipientAndCalldata(false, amount, recipient, dataToCall, gasLimit, feePerGas);
     }
 
-    function testDropMessageMocking() public {
-        MockScrollMessenger mockMessenger = new MockScrollMessenger();
-        gateway = _deployGateway(address(mockMessenger));
-        gateway.initialize(address(counterpartGateway), address(router), address(mockMessenger));
-
-        // only messenger can call, revert
-        hevm.expectRevert(ErrorCallerIsNotMessenger.selector);
-        gateway.onDropMessage(new bytes(0));
-
-        // only called in drop context, revert
-        hevm.expectRevert(ErrorNotInDropMessageContext.selector);
-        mockMessenger.callTarget(
-            address(gateway),
-            abi.encodeWithSelector(gateway.onDropMessage.selector, new bytes(0))
-        );
-
-        mockMessenger.setXDomainMessageSender(ScrollConstants.DROP_XDOMAIN_MESSAGE_SENDER);
-
-        // invalid selector, revert
-        hevm.expectRevert("invalid selector");
-        mockMessenger.callTarget(
-            address(gateway),
-            abi.encodeWithSelector(gateway.onDropMessage.selector, new bytes(4))
-        );
-
-        bytes memory message = abi.encodeWithSelector(
-            IL2ERC20Gateway.finalizeDepositERC20.selector,
-            address(l1Token),
-            address(l2Token),
-            address(this),
-            address(this),
-            100,
-            new bytes(0)
-        );
-
-        // nonzero msg.value, revert
-        hevm.expectRevert("nonzero msg.value");
-        mockMessenger.callTarget{value: 1}(
-            address(gateway),
-            abi.encodeWithSelector(gateway.onDropMessage.selector, message)
-        );
-    }
-
-    function testDropMessage(
-        uint256 amount,
-        address recipient,
-        bytes memory dataToCall
-    ) public {
-        // message 0 is append here
-        gateway.updateTokenMapping{value: 1 ether}(address(l1Token), address(l2Token));
-
-        // finalize message 0
-        hevm.startPrank(address(rollup));
-        messageQueueV1.popCrossDomainMessage(0, 1, 0);
-        messageQueueV1.finalizePoppedCrossDomainMessage(1);
-        hevm.stopPrank();
-        assertEq(messageQueueV1.pendingQueueIndex(), 1);
-        assertEq(messageQueueV1.nextUnfinalizedQueueIndex(), 1);
-
-        amount = bound(amount, 1, l1Token.balanceOf(address(this)));
-        bytes memory message = abi.encodeWithSelector(
-            IL2ERC20Gateway.finalizeDepositERC20.selector,
-            address(l1Token),
-            address(l2Token),
-            address(this),
-            recipient,
-            amount,
-            dataToCall
-        );
-        gateway.depositERC20AndCall(address(l1Token), recipient, amount, dataToCall, defaultGasLimit);
-
-        // skip message 1
-        hevm.startPrank(address(rollup));
-        messageQueueV1.popCrossDomainMessage(1, 1, 0x1);
-        messageQueueV1.finalizePoppedCrossDomainMessage(2);
-        assertEq(messageQueueV1.pendingQueueIndex(), 2);
-        assertEq(messageQueueV1.nextUnfinalizedQueueIndex(), 2);
-        hevm.stopPrank();
-
-        // drop message 1
-        hevm.expectEmit(true, true, false, true);
-        emit RefundERC20(address(l1Token), address(this), amount);
-
-        uint256 balance = l1Token.balanceOf(address(this));
-        l1Messenger.dropMessage(address(gateway), address(counterpartGateway), 0, 1, message);
-        assertEq(balance + amount, l1Token.balanceOf(address(this)));
-    }
-
     function testFinalizeWithdrawERC20FailedMocking(
         address sender,
         address recipient,
diff --git a/src/test/L1ERC1155Gateway.t.sol b/src/test/L1ERC1155Gateway.t.sol
index ef707693..ad4c9589 100644
--- a/src/test/L1ERC1155Gateway.t.sol
+++ b/src/test/L1ERC1155Gateway.t.sol
@@ -160,127 +160,6 @@ contract L1ERC1155GatewayTest is L1GatewayTestBase, ERC1155TokenReceiver {
         _testBatchDepositERC1155WithRecipient(tokenCount, amount, recipient, gasLimit, feePerGas);
     }
 
-    function testDropMessageMocking() public {
-        MockScrollMessenger mockMessenger = new MockScrollMessenger();
-        gateway = _deployGateway(address(mockMessenger));
-        gateway.initialize(address(counterpartGateway), address(mockMessenger));
-
-        // only messenger can call, revert
-        hevm.expectRevert(ErrorCallerIsNotMessenger.selector);
-        gateway.onDropMessage(new bytes(0));
-
-        // only called in drop context, revert
-        hevm.expectRevert(ErrorNotInDropMessageContext.selector);
-        mockMessenger.callTarget(
-            address(gateway),
-            abi.encodeWithSelector(gateway.onDropMessage.selector, new bytes(0))
-        );
-
-        mockMessenger.setXDomainMessageSender(ScrollConstants.DROP_XDOMAIN_MESSAGE_SENDER);
-
-        // invalid selector, revert
-        hevm.expectRevert("invalid selector");
-        mockMessenger.callTarget(
-            address(gateway),
-            abi.encodeWithSelector(gateway.onDropMessage.selector, new bytes(4))
-        );
-
-        bytes memory message = abi.encodeWithSelector(
-            IL2ERC1155Gateway.finalizeDepositERC1155.selector,
-            address(l1Token),
-            address(l2Token),
-            address(this),
-            address(this),
-            0,
-            0
-        );
-
-        // nonzero msg.value, revert
-        hevm.expectRevert("nonzero msg.value");
-        mockMessenger.callTarget{value: 1}(
-            address(gateway),
-            abi.encodeWithSelector(gateway.onDropMessage.selector, message)
-        );
-    }
-
-    function testDropMessage(uint256 tokenId, uint256 amount) public {
-        gateway.updateTokenMapping(address(l1Token), address(l2Token));
-
-        tokenId = bound(tokenId, 0, TOKEN_COUNT - 1);
-        amount = bound(amount, 1, MAX_TOKEN_BALANCE);
-        bytes memory message = abi.encodeWithSelector(
-            IL2ERC1155Gateway.finalizeDepositERC1155.selector,
-            address(l1Token),
-            address(l2Token),
-            address(this),
-            address(this),
-            tokenId,
-            amount
-        );
-        gateway.depositERC1155(address(l1Token), tokenId, amount, defaultGasLimit);
-
-        // skip message 0
-        hevm.startPrank(address(rollup));
-        messageQueueV1.popCrossDomainMessage(0, 1, 0x1);
-        messageQueueV1.finalizePoppedCrossDomainMessage(1);
-        assertEq(messageQueueV1.nextUnfinalizedQueueIndex(), 1);
-        assertEq(messageQueueV1.pendingQueueIndex(), 1);
-        hevm.stopPrank();
-
-        // drop message 0
-        hevm.expectEmit(true, true, false, true);
-        emit RefundERC1155(address(l1Token), address(this), tokenId, amount);
-
-        uint256 balance = l1Token.balanceOf(address(this), tokenId);
-        l1Messenger.dropMessage(address(gateway), address(counterpartGateway), 0, 0, message);
-        assertEq(balance + amount, l1Token.balanceOf(address(this), tokenId));
-    }
-
-    function testDropMessageBatch(uint256 tokenCount, uint256 amount) public {
-        tokenCount = bound(tokenCount, 1, TOKEN_COUNT);
-        amount = bound(amount, 1, MAX_TOKEN_BALANCE);
-        gateway.updateTokenMapping(address(l1Token), address(l2Token));
-
-        uint256[] memory _tokenIds = new uint256[](tokenCount);
-        uint256[] memory _amounts = new uint256[](tokenCount);
-        for (uint256 i = 0; i < tokenCount; i++) {
-            _tokenIds[i] = i;
-            _amounts[i] = amount;
-        }
-
-        bytes memory message = abi.encodeWithSelector(
-            IL2ERC1155Gateway.finalizeBatchDepositERC1155.selector,
-            address(l1Token),
-            address(l2Token),
-            address(this),
-            address(this),
-            _tokenIds,
-            _amounts
-        );
-        gateway.batchDepositERC1155(address(l1Token), _tokenIds, _amounts, defaultGasLimit);
-
-        // skip message 0
-        hevm.startPrank(address(rollup));
-        messageQueueV1.popCrossDomainMessage(0, 1, 0x1);
-        messageQueueV1.finalizePoppedCrossDomainMessage(1);
-        assertEq(messageQueueV1.nextUnfinalizedQueueIndex(), 1);
-        assertEq(messageQueueV1.pendingQueueIndex(), 1);
-        hevm.stopPrank();
-
-        // drop message 0
-        hevm.expectEmit(true, true, false, true);
-        emit BatchRefundERC1155(address(l1Token), address(this), _tokenIds, _amounts);
-
-        uint256[] memory balances = new uint256[](tokenCount);
-        for (uint256 i = 0; i < tokenCount; i++) {
-            balances[i] = l1Token.balanceOf(address(this), _tokenIds[i]);
-        }
-        l1Messenger.dropMessage(address(gateway), address(counterpartGateway), 0, 0, message);
-        for (uint256 i = 0; i < tokenCount; i++) {
-            assertEq(balances[i] + _amounts[i], l1Token.balanceOf(address(this), _tokenIds[i]));
-        }
-    }
-
     function testFinalizeWithdrawERC1155FailedMocking(
         address sender,
         address recipient,
diff --git a/src/test/L1ERC721Gateway.t.sol b/src/test/L1ERC721Gateway.t.sol
index edebe9ea..9cd52de7 100644
--- a/src/test/L1ERC721Gateway.t.sol
+++ b/src/test/L1ERC721Gateway.t.sol
@@ -151,119 +151,6 @@ contract L1ERC721GatewayTest is L1GatewayTestBase, ERC721TokenReceiver {
         _testBatchDepositERC721WithRecipient(tokenCount, recipient, gasLimit, feePerGas);
     }
 
-    function testDropMessageMocking() public {
-        MockScrollMessenger mockMessenger = new MockScrollMessenger();
-        gateway = _deployGateway(address(mockMessenger));
-        gateway.initialize(address(counterpartGateway), address(mockMessenger));
-
-        // only messenger can call, revert
-        hevm.expectRevert(ErrorCallerIsNotMessenger.selector);
-        gateway.onDropMessage(new bytes(0));
-
-        // only called in drop context, revert
-        hevm.expectRevert(ErrorNotInDropMessageContext.selector);
-        mockMessenger.callTarget(
-            address(gateway),
-            abi.encodeWithSelector(gateway.onDropMessage.selector, new bytes(0))
-        );
-
-        mockMessenger.setXDomainMessageSender(ScrollConstants.DROP_XDOMAIN_MESSAGE_SENDER);
-
-        // invalid selector, revert
-        hevm.expectRevert("invalid selector");
-        mockMessenger.callTarget(
-            address(gateway),
-            abi.encodeWithSelector(gateway.onDropMessage.selector, new bytes(4))
-        );
-
-        bytes memory message = abi.encodeWithSelector(
-            IL2ERC721Gateway.finalizeDepositERC721.selector,
-            address(l1Token),
-            address(l2Token),
-            address(this),
-            address(this),
-            0
-        );
-
-        // nonzero msg.value, revert
-        hevm.expectRevert("nonzero msg.value");
-        mockMessenger.callTarget{value: 1}(
-            address(gateway),
-            abi.encodeWithSelector(gateway.onDropMessage.selector, message)
-        );
-    }
-
-    function testDropMessage(uint256 tokenId) public {
-        gateway.updateTokenMapping(address(l1Token), address(l2Token));
-
-        tokenId = bound(tokenId, 0, TOKEN_COUNT - 1);
-        bytes memory message = abi.encodeWithSelector(
-            IL2ERC721Gateway.finalizeDepositERC721.selector,
-            address(l1Token),
-            address(l2Token),
-            address(this),
-            address(this),
-            tokenId
-        );
-        gateway.depositERC721(address(l1Token), tokenId, defaultGasLimit);
-
-        // skip message 0
-        hevm.startPrank(address(rollup));
-        messageQueueV1.popCrossDomainMessage(0, 1, 0x1);
-        messageQueueV1.finalizePoppedCrossDomainMessage(1);
-        assertEq(messageQueueV1.nextUnfinalizedQueueIndex(), 1);
-        assertEq(messageQueueV1.pendingQueueIndex(), 1);
-        hevm.stopPrank();
-
-        // drop message 0
-        hevm.expectEmit(true, true, false, true);
-        emit RefundERC721(address(l1Token), address(this), tokenId);
-
-        assertEq(l1Token.ownerOf(tokenId), address(gateway));
-        l1Messenger.dropMessage(address(gateway), address(counterpartGateway), 0, 0, message);
-        assertEq(l1Token.ownerOf(tokenId), address(this));
-    }
-
-    function testDropMessageBatch(uint256 tokenCount) public {
-        tokenCount = bound(tokenCount, 1, TOKEN_COUNT);
-        gateway.updateTokenMapping(address(l1Token), address(l2Token));
-
-        uint256[] memory _tokenIds = new uint256[](tokenCount);
-        for (uint256 i = 0; i < tokenCount; i++) {
-            _tokenIds[i] = i;
-        }
-
-        bytes memory message = abi.encodeWithSelector(
-            IL2ERC721Gateway.finalizeBatchDepositERC721.selector,
-            address(l1Token),
-            address(l2Token),
-            address(this),
-            address(this),
-            _tokenIds
-        );
-        gateway.batchDepositERC721(address(l1Token), _tokenIds, defaultGasLimit);
-
-        // skip message 0
-        hevm.startPrank(address(rollup));
-        messageQueueV1.popCrossDomainMessage(0, 1, 0x1);
-        messageQueueV1.finalizePoppedCrossDomainMessage(1);
-        assertEq(messageQueueV1.nextUnfinalizedQueueIndex(), 1);
-        assertEq(messageQueueV1.pendingQueueIndex(), 1);
-        hevm.stopPrank();
-
-        // drop message 0
-        hevm.expectEmit(true, true, false, true);
-        emit BatchRefundERC721(address(l1Token), address(this), _tokenIds);
-        for (uint256 i = 0; i < tokenCount; i++) {
-            assertEq(l1Token.ownerOf(_tokenIds[i]), address(gateway));
-        }
-
-        l1Messenger.dropMessage(address(gateway), address(counterpartGateway), 0, 0, message);
-        for (uint256 i = 0; i < tokenCount; i++) {
-            assertEq(l1Token.ownerOf(_tokenIds[i]), address(this));
-        }
-    }
-
     function testFinalizeWithdrawERC721FailedMocking(
         address sender,
         address recipient,
diff --git a/src/test/L1ETHGateway.t.sol b/src/test/L1ETHGateway.t.sol
index 4b5ebe83..8c5460c6 100644
--- a/src/test/L1ETHGateway.t.sol
+++ b/src/test/L1ETHGateway.t.sol
@@ -104,85 +104,6 @@ contract L1ETHGatewayTest is L1GatewayTestBase {
         _depositETHWithRecipientAndCalldata(true, amount, recipient, dataToCall, gasLimit, feePerGas);
     }
 
-    function testDropMessageMocking() public {
-        MockScrollMessenger mockMessenger = new MockScrollMessenger();
-        gateway = _deployGateway(address(mockMessenger));
-        gateway.initialize(address(counterpartGateway), address(router), address(mockMessenger));
-
-        // only messenger can call, revert
-        hevm.expectRevert(ErrorCallerIsNotMessenger.selector);
-        gateway.onDropMessage(new bytes(0));
-
-        // only called in drop context, revert
-        hevm.expectRevert(ErrorNotInDropMessageContext.selector);
-        mockMessenger.callTarget(
-            address(gateway),
-            abi.encodeWithSelector(gateway.onDropMessage.selector, new bytes(0))
-        );
-
-        mockMessenger.setXDomainMessageSender(ScrollConstants.DROP_XDOMAIN_MESSAGE_SENDER);
-
-        // invalid selector, revert
-        hevm.expectRevert("invalid selector");
-        mockMessenger.callTarget(
-            address(gateway),
-            abi.encodeWithSelector(gateway.onDropMessage.selector, new bytes(4))
-        );
-
-        bytes memory message = abi.encodeWithSelector(
-            IL2ETHGateway.finalizeDepositETH.selector,
-            address(this),
-            address(this),
-            100,
-            new bytes(0)
-        );
-
-        // msg.value mismatch, revert
-        hevm.expectRevert("msg.value mismatch");
-        mockMessenger.callTarget{value: 99}(
-            address(gateway),
-            abi.encodeWithSelector(gateway.onDropMessage.selector, message)
-        );
-    }
-
-    function testDropMessage(
-        uint256 amount,
-        address recipient,
-        bytes memory dataToCall
-    ) public {
-        amount = bound(amount, 1, address(this).balance);
-        bytes memory message = abi.encodeWithSelector(
-            IL2ETHGateway.finalizeDepositETH.selector,
-            address(this),
-            recipient,
-            amount,
-            dataToCall
-        );
-        gateway.depositETHAndCall{value: amount}(recipient, amount, dataToCall, defaultGasLimit);
-
-        // skip message 0
-        hevm.startPrank(address(rollup));
-        messageQueueV1.popCrossDomainMessage(0, 1, 0x1);
-        messageQueueV1.finalizePoppedCrossDomainMessage(1);
-        assertEq(messageQueueV1.nextUnfinalizedQueueIndex(), 1);
-        assertEq(messageQueueV1.pendingQueueIndex(), 1);
-        hevm.stopPrank();
-
-        // ETH transfer failed, revert
-        revertOnReceive = true;
-        hevm.expectRevert("ETH transfer failed");
-        l1Messenger.dropMessage(address(gateway), address(counterpartGateway), amount, 0, message);
-
-        // drop message 0
-        hevm.expectEmit(true, true, false, true);
-        emit RefundETH(address(this), amount);
-
-        revertOnReceive = false;
-        uint256 balance = address(this).balance;
-        l1Messenger.dropMessage(address(gateway), address(counterpartGateway), amount, 0, message);
-        assertEq(balance + amount, address(this).balance);
-    }
-
     function testFinalizeWithdrawETHFailedMocking(
         address sender,
         address recipient,
diff --git a/src/test/L1ReverseCustomERC20Gateway.t.sol b/src/test/L1ReverseCustomERC20Gateway.t.sol
index 0886a1f5..d4972191 100644
--- a/src/test/L1ReverseCustomERC20Gateway.t.sol
+++ b/src/test/L1ReverseCustomERC20Gateway.t.sol
@@ -147,53 +147,6 @@ contract L1ReverseCustomERC20GatewayTest is L1GatewayTestBase {
         _depositERC20(true, 2, amount, recipient, dataToCall, gasLimit, feePerGas);
     }
 
-    function testDropMessage(
-        uint256 amount,
-        address recipient,
-        bytes memory dataToCall
-    ) public {
-        // message 0 is append here
-        gateway.updateTokenMapping{value: 1 ether}(address(l1Token), address(l2Token));
-
-        // finalize message 0
-        hevm.startPrank(address(rollup));
-        messageQueueV1.popCrossDomainMessage(0, 1, 0);
-        messageQueueV1.finalizePoppedCrossDomainMessage(1);
-        hevm.stopPrank();
-        assertEq(messageQueueV1.pendingQueueIndex(), 1);
-        assertEq(messageQueueV1.nextUnfinalizedQueueIndex(), 1);
-
-        amount = bound(amount, 1, l1Token.balanceOf(address(this)));
-        bytes memory message = abi.encodeWithSelector(
-            IL2ERC20Gateway.finalizeDepositERC20.selector,
-            address(l1Token),
-            address(l2Token),
-            address(this),
-            recipient,
-            amount,
-            dataToCall
-        );
-        gateway.depositERC20AndCall(address(l1Token), recipient, amount, dataToCall, defaultGasLimit);
-
-        // skip message 1
-        hevm.startPrank(address(rollup));
-        messageQueueV1.popCrossDomainMessage(1, 1, 0x1);
-        messageQueueV1.finalizePoppedCrossDomainMessage(2);
-        assertEq(messageQueueV1.pendingQueueIndex(), 2);
-        assertEq(messageQueueV1.nextUnfinalizedQueueIndex(), 2);
-        hevm.stopPrank();
-
-        // drop message 1
-        hevm.expectEmit(true, true, false, true);
-        emit RefundERC20(address(l1Token), address(this), amount);
-
-        uint256 balance = l1Token.balanceOf(address(this));
-        uint256 gatewayBalance = l1Token.balanceOf(address(gateway));
-        l1Messenger.dropMessage(address(gateway), address(counterpartGateway), 0, 1, message);
-        assertEq(balance + amount, l1Token.balanceOf(address(this)));
-        assertEq(gatewayBalance, l1Token.balanceOf(address(gateway)));
-    }
-
     function testFinalizeWithdrawERC20(
         address sender,
         uint256 amount,
diff --git a/src/test/L1ScrollMessengerTest.t.sol b/src/test/L1ScrollMessengerTest.t.sol
index d29c70a7..74aaad35 100644
--- a/src/test/L1ScrollMessengerTest.t.sol
+++ b/src/test/L1ScrollMessengerTest.t.sol
@@ -237,8 +237,6 @@ contract L1ScrollMessengerTest is L1GatewayTestBase {
         l1Messenger.relayMessageWithProof(address(0), address(0), 0, 0, new bytes(0), _proof);
         hevm.expectRevert("Pausable: paused");
         l1Messenger.replayMessage(address(0), address(0), 0, 0, new bytes(0), 0, address(0));
-        hevm.expectRevert("Pausable: paused");
-        l1Messenger.dropMessage(address(0), address(0), 0, 0, new bytes(0));
 
         // unpause
         l1Messenger.setPause(false);
@@ -275,111 +273,4 @@ contract L1ScrollMessengerTest is L1GatewayTestBase {
         _fee = messageQueueV2.estimateL2BaseFee() * gasLimit;
         l1Messenger.sendMessage{value: _fee + value}(address(0), value, hex"0011220033", gasLimit);
     }
-
-    /* comments out, it is tested in `src/test/MessageQueueSwitch.t.sol`.
-    function testDropMessage() external {
-        // Provided message has not been enqueued, revert
-        hevm.expectRevert("Provided message has not been enqueued");
-        l1Messenger.dropMessage(address(0), address(0), 0, 0, new bytes(0));
-
-        // send one message with nonce 0
-        l1Messenger.sendMessage(address(0), 0, new bytes(0), defaultGasLimit);
-        assertEq(messageQueueV1.nextCrossDomainMessageIndex(), 1);
-
-        // drop pending message, revert
-        hevm.expectRevert("cannot drop pending message");
-        l1Messenger.dropMessage(address(this), address(0), 0, 0, new bytes(0));
-
-        l1Messenger.updateMaxReplayTimes(10);
-
-        // replay 1 time
-        l1Messenger.replayMessage(address(this), address(0), 0, 0, new bytes(0), defaultGasLimit, address(0));
-        assertEq(messageQueueV1.nextCrossDomainMessageIndex(), 2);
-
-        // skip all 2 messages
-        hevm.startPrank(address(rollup));
-        messageQueueV1.popCrossDomainMessage(0, 2, 0x3);
-        messageQueueV1.finalizePoppedCrossDomainMessage(2);
-        assertEq(messageQueueV1.nextUnfinalizedQueueIndex(), 2);
-        assertEq(messageQueueV1.pendingQueueIndex(), 2);
-        hevm.stopPrank();
-        for (uint256 i = 0; i < 2; ++i) {
-            assertBoolEq(messageQueueV1.isMessageSkipped(i), true);
-            assertBoolEq(messageQueueV1.isMessageDropped(i), false);
-        }
-        hevm.expectEmit(false, false, false, true);
-        emit OnDropMessageCalled(new bytes(0));
-        l1Messenger.dropMessage(address(this), address(0), 0, 0, new bytes(0));
-        for (uint256 i = 0; i < 2; ++i) {
-            assertBoolEq(messageQueueV1.isMessageSkipped(i), true);
-            assertBoolEq(messageQueueV1.isMessageDropped(i), true);
-        }
-
-        // send one message with nonce 2 and replay 3 times
-        l1Messenger.sendMessage(address(0), 0, new bytes(0), defaultGasLimit);
-        assertEq(messageQueueV1.nextCrossDomainMessageIndex(), 3);
-        for (uint256 i = 0; i < 3; i++) {
-            l1Messenger.replayMessage(address(this), address(0), 0, 2, new bytes(0), defaultGasLimit, address(0));
-        }
-        assertEq(messageQueueV1.nextCrossDomainMessageIndex(), 6);
-
-        // only first 3 are skipped
-        hevm.startPrank(address(rollup));
-        messageQueueV1.popCrossDomainMessage(2, 4, 0x7);
-        messageQueueV1.finalizePoppedCrossDomainMessage(6);
-        assertEq(messageQueueV1.nextUnfinalizedQueueIndex(), 6);
-        assertEq(messageQueueV1.pendingQueueIndex(), 6);
-        hevm.stopPrank();
-        for (uint256 i = 2; i < 6; i++) {
-            assertBoolEq(messageQueueV1.isMessageSkipped(i), i < 5);
-            assertBoolEq(messageQueueV1.isMessageDropped(i), false);
-        }
-
-        // drop non-skipped message, revert
-        hevm.expectRevert("drop non-skipped message");
-        l1Messenger.dropMessage(address(this), address(0), 0, 2, new bytes(0));
-
-        // send one message with nonce 6 and replay 4 times
-        l1Messenger.sendMessage(address(0), 0, new bytes(0), defaultGasLimit);
-        for (uint256 i = 0; i < 4; i++) {
-            l1Messenger.replayMessage(address(this), address(0), 0, 6, new bytes(0), defaultGasLimit, address(0));
-        }
-        assertEq(messageQueueV1.nextCrossDomainMessageIndex(), 11);
-
-        // skip all 5 messages
-        hevm.startPrank(address(rollup));
-        messageQueueV1.popCrossDomainMessage(6, 5, 0x1f);
-        messageQueueV1.finalizePoppedCrossDomainMessage(11);
-        assertEq(messageQueueV1.nextUnfinalizedQueueIndex(), 11);
-        assertEq(messageQueueV1.pendingQueueIndex(), 11);
-        hevm.stopPrank();
-        for (uint256 i = 6; i < 11; ++i) {
-            assertBoolEq(messageQueueV1.isMessageSkipped(i), true);
-            assertBoolEq(messageQueueV1.isMessageDropped(i), false);
-        }
-        hevm.expectEmit(false, false, false, true);
-        emit OnDropMessageCalled(new bytes(0));
-        l1Messenger.dropMessage(address(this), address(0), 0, 6, new bytes(0));
-        for (uint256 i = 6; i < 11; ++i) {
-            assertBoolEq(messageQueueV1.isMessageSkipped(i), true);
-            assertBoolEq(messageQueueV1.isMessageDropped(i), true);
-        }
-
-        // Message already dropped, revert
-        hevm.expectRevert("Message already dropped");
-        l1Messenger.dropMessage(address(this), address(0), 0, 0, new bytes(0));
-        hevm.expectRevert("Message already dropped");
-        l1Messenger.dropMessage(address(this), address(0), 0, 6, new bytes(0));
-
-        // replay dropped message, revert
-        hevm.expectRevert("Message already dropped");
-        l1Messenger.replayMessage(address(this), address(0), 0, 0, new bytes(0), defaultGasLimit, address(0));
-        hevm.expectRevert("Message already dropped");
-        l1Messenger.replayMessage(address(this), address(0), 0, 6, new bytes(0), defaultGasLimit, address(0));
-    }
-    */
-
-    function onDropMessage(bytes memory message) external payable {
-        emit OnDropMessageCalled(message);
-    }
 }
diff --git a/src/test/L1StandardERC20Gateway.t.sol b/src/test/L1StandardERC20Gateway.t.sol
index 909b1f3f..08043b2e 100644
--- a/src/test/L1StandardERC20Gateway.t.sol
+++ b/src/test/L1StandardERC20Gateway.t.sol
@@ -218,90 +218,6 @@ contract L1StandardERC20GatewayTest is L1GatewayTestBase {
         assertEq(balanceBefore + amount - fee, balanceAfter);
     }
 
-    function testDropMessageMocking() public {
-        MockScrollMessenger mockMessenger = new MockScrollMessenger();
-        gateway = _deployGateway(address(mockMessenger));
-        gateway.initialize(
-            address(counterpartGateway),
-            address(router),
-            address(mockMessenger),
-            address(template),
-            address(factory)
-        );
-
-        // only messenger can call, revert
-        hevm.expectRevert(ErrorCallerIsNotMessenger.selector);
-        gateway.onDropMessage(new bytes(0));
-
-        // only called in drop context, revert
-        hevm.expectRevert(ErrorNotInDropMessageContext.selector);
-        mockMessenger.callTarget(
-            address(gateway),
-            abi.encodeWithSelector(gateway.onDropMessage.selector, new bytes(0))
-        );
-
-        mockMessenger.setXDomainMessageSender(ScrollConstants.DROP_XDOMAIN_MESSAGE_SENDER);
-
-        // invalid selector, revert
-        hevm.expectRevert("invalid selector");
-        mockMessenger.callTarget(
-            address(gateway),
-            abi.encodeWithSelector(gateway.onDropMessage.selector, new bytes(4))
-        );
-
-        bytes memory message = abi.encodeWithSelector(
-            IL2ERC20Gateway.finalizeDepositERC20.selector,
-            address(l1Token),
-            address(l2Token),
-            address(this),
-            address(this),
-            100,
-            new bytes(0)
-        );
-
-        // nonzero msg.value, revert
-        hevm.expectRevert("nonzero msg.value");
-        mockMessenger.callTarget{value: 1}(
-            address(gateway),
-            abi.encodeWithSelector(gateway.onDropMessage.selector, message)
-        );
-    }
-
-    function testDropMessage(
-        uint256 amount,
-        address recipient,
-        bytes memory dataToCall
-    ) public {
-        amount = bound(amount, 1, l1Token.balanceOf(address(this)) / 2);
-        bytes memory message = abi.encodeWithSelector(
-            IL2ERC20Gateway.finalizeDepositERC20.selector,
-            address(l1Token),
-            address(l2Token),
-            address(this),
-            recipient,
-            amount,
-            abi.encode(true, abi.encode(dataToCall, abi.encode(l1Token.symbol(), l1Token.name(), l1Token.decimals())))
-        );
-        gateway.depositERC20AndCall(address(l1Token), recipient, amount, dataToCall, defaultGasLimit);
-        gateway.depositERC20AndCall(address(l1Token), recipient, amount, dataToCall, defaultGasLimit);
-
-        // skip message 0 and 1
-        hevm.startPrank(address(rollup));
-        messageQueueV1.popCrossDomainMessage(0, 2, 0x3);
-        messageQueueV1.finalizePoppedCrossDomainMessage(2);
-        assertEq(messageQueueV1.nextUnfinalizedQueueIndex(), 2);
-        assertEq(messageQueueV1.pendingQueueIndex(), 2);
-        hevm.stopPrank();
-
-        // drop message 1
-        hevm.expectEmit(true, true, false, true);
-        emit RefundERC20(address(l1Token), address(this), amount);
-
-        uint256 balance = l1Token.balanceOf(address(this));
-        l1Messenger.dropMessage(address(gateway), address(counterpartGateway), 0, 1, message);
-        assertEq(balance + amount, l1Token.balanceOf(address(this)));
-    }
-
     function testFinalizeWithdrawERC20FailedMocking(
         address sender,
         address recipient,
diff --git a/src/test/L1WETHGateway.t.sol b/src/test/L1WETHGateway.t.sol
index d93ab583..a4f3fb6f 100644
--- a/src/test/L1WETHGateway.t.sol
+++ b/src/test/L1WETHGateway.t.sol
@@ -143,101 +143,6 @@ contract L1WETHGatewayTest is L1GatewayTestBase {
         _depositERC20WithRecipientAndCalldata(true, amount, recipient, dataToCall, gasLimit, feePerGas);
     }
 
-    function testDropMessageMocking() public {
-        MockScrollMessenger mockMessenger = new MockScrollMessenger();
-        gateway = _deployGateway(address(mockMessenger));
-        gateway.initialize(address(counterpartGateway), address(router), address(mockMessenger));
-
-        // only messenger can call, revert
-        hevm.expectRevert(ErrorCallerIsNotMessenger.selector);
-        gateway.onDropMessage(new bytes(0));
-
-        // only called in drop context, revert
-        hevm.expectRevert(ErrorNotInDropMessageContext.selector);
-        mockMessenger.callTarget(
-            address(gateway),
-            abi.encodeWithSelector(gateway.onDropMessage.selector, new bytes(0))
-        );
-
-        mockMessenger.setXDomainMessageSender(ScrollConstants.DROP_XDOMAIN_MESSAGE_SENDER);
-
-        // invalid selector, revert
-        hevm.expectRevert("invalid selector");
-        mockMessenger.callTarget(
-            address(gateway),
-            abi.encodeWithSelector(gateway.onDropMessage.selector, new bytes(4))
-        );
-
-        bytes memory message = abi.encodeWithSelector(
-            IL2ERC20Gateway.finalizeDepositERC20.selector,
-            address(l1weth),
-            address(l2weth),
-            address(this),
-            address(this),
-            100,
-            new bytes(0)
-        );
-
-        // token not WETH, revert
-        hevm.expectRevert("token not WETH");
-        mockMessenger.callTarget(
-            address(gateway),
-            abi.encodeWithSelector(
-                gateway.onDropMessage.selector,
-                abi.encodeWithSelector(
-                    IL2ERC20Gateway.finalizeDepositERC20.selector,
-                    address(l2weth),
-                    address(l2weth),
-                    address(this),
-                    address(this),
-                    100,
-                    new bytes(0)
-                )
-            )
-        );
-
-        // msg.value mismatch, revert
-        hevm.expectRevert("msg.value mismatch");
-        mockMessenger.callTarget{value: 99}(
-            address(gateway),
-            abi.encodeWithSelector(gateway.onDropMessage.selector, message)
-        );
-    }
-
-    function testDropMessage(
-        uint256 amount,
-        address recipient,
-        bytes memory dataToCall
-    ) public {
-        amount = bound(amount, 1, l1weth.balanceOf(address(this)));
-        bytes memory message = abi.encodeWithSelector(
-            IL2ERC20Gateway.finalizeDepositERC20.selector,
-            address(l1weth),
-            address(l2weth),
-            address(this),
-            recipient,
-            amount,
-            dataToCall
-        );
-        gateway.depositERC20AndCall(address(l1weth), recipient, amount, dataToCall, defaultGasLimit);
-
-        // skip message 0
-        hevm.startPrank(address(rollup));
-        messageQueueV1.popCrossDomainMessage(0, 1, 0x1);
-        messageQueueV1.finalizePoppedCrossDomainMessage(1);
-        assertEq(messageQueueV1.nextUnfinalizedQueueIndex(), 1);
-        assertEq(messageQueueV1.pendingQueueIndex(), 1);
-        hevm.stopPrank();
-
-        // drop message 0
-        hevm.expectEmit(true, true, false, true);
-        emit RefundERC20(address(l1weth), address(this), amount);
-
-        uint256 balance = l1weth.balanceOf(address(this));
-        l1Messenger.dropMessage(address(gateway), address(counterpartGateway), amount, 0, message);
-        assertEq(balance + amount, l1weth.balanceOf(address(this)));
-    }
-
     function testFinalizeWithdrawERC20FailedMocking(
         address sender,
         address recipient,
diff --git a/src/test/TokenRateLimiter.t.sol b/src/test/TokenRateLimiter.t.sol
deleted file mode 100644
index 5eb44b14..00000000
--- a/src/test/TokenRateLimiter.t.sol
+++ /dev/null
@@ -1,82 +0,0 @@
-// SPDX-License-Identifier: MIT
-
-pragma solidity =0.8.24;
-
-import {DSTestPlus} from "solmate/test/utils/DSTestPlus.sol";
-
-import {TokenRateLimiter} from "../rate-limiter/TokenRateLimiter.sol";
-import {ITokenRateLimiter} from "../rate-limiter/ITokenRateLimiter.sol";
-
-contract TokenRateLimiterTest is DSTestPlus {
-    event UpdateTotalLimit(address indexed token, uint256 oldTotalLimit, uint256 newTotalLimit);
-
-    TokenRateLimiter private limiter;
-
-    function setUp() public {
-        hevm.warp(86400);
-        limiter = new TokenRateLimiter(86400);
-    }
-
-    function testUpdateTotalLimit(address _token, uint104 _newTotalLimit) external {
-        hevm.assume(_newTotalLimit > 0);
-
-        // not admin, revert
-        hevm.startPrank(address(1));
-        hevm.expectRevert(
-            "AccessControl: account 0x0000000000000000000000000000000000000001 is missing role 0x0000000000000000000000000000000000000000000000000000000000000000"
-        );
-        limiter.updateTotalLimit(_token, _newTotalLimit);
-        hevm.stopPrank();
-
-        // zero revert
-        hevm.expectRevert(abi.encodeWithSelector(ITokenRateLimiter.TotalLimitIsZero.selector, _token));
-        limiter.updateTotalLimit(_token, 0);
-
-        // success
-        hevm.expectEmit(true, false, false, true);
-        emit UpdateTotalLimit(_token, 0 ether, _newTotalLimit);
-        limiter.updateTotalLimit(_token, _newTotalLimit);
-        (, uint104 _totalLimit, ) = limiter.currentPeriod(_token);
-        assertEq(_totalLimit, _newTotalLimit);
-    }
-
-    function testAddUsedAmount(address _token) external {
-        // non-spender, revert
-        hevm.startPrank(address(1));
-        hevm.expectRevert(
-            "AccessControl: account 0x0000000000000000000000000000000000000001 is missing role 0x267f05081a073059ae452e6ac77ec189636e43e41051d4c3ec760734b3d173cb"
-        );
-        limiter.addUsedAmount(_token, 0);
-        hevm.stopPrank();
-
-        limiter.grantRole(bytes32(0x267f05081a073059ae452e6ac77ec189636e43e41051d4c3ec760734b3d173cb), address(this));
-        limiter.updateTotalLimit(_token, 100 ether);
-
-        // exceed total limit on first call
-        hevm.expectRevert(abi.encodeWithSelector(ITokenRateLimiter.ExceedTotalLimit.selector, _token));
-        limiter.addUsedAmount(_token, 100 ether + 1);
-        _checkTotalCurrentPeriodAmountAmount(_token, 0);
-
-        // exceed total limit on second call
-        limiter.addUsedAmount(_token, 50 ether);
-        _checkTotalCurrentPeriodAmountAmount(_token, 50 ether);
-        hevm.expectRevert(abi.encodeWithSelector(ITokenRateLimiter.ExceedTotalLimit.selector, _token));
-        limiter.addUsedAmount(_token, 50 ether + 1);
-        _checkTotalCurrentPeriodAmountAmount(_token, 50 ether);
-
-        // one period passed
-        hevm.warp(86400 * 2);
-        limiter.addUsedAmount(_token, 1 ether);
-        _checkTotalCurrentPeriodAmountAmount(_token, 1 ether);
-
-        // exceed
-        hevm.expectRevert(abi.encodeWithSelector(ITokenRateLimiter.ExceedTotalLimit.selector, _token));
-        limiter.addUsedAmount(_token, 99 ether + 1);
-        _checkTotalCurrentPeriodAmountAmount(_token, 1 ether);
-    }
-
-    function _checkTotalCurrentPeriodAmountAmount(address token, uint256 expected) internal {
-        (, , uint256 totalAmount) = limiter.currentPeriod(token);
-        assertEq(totalAmount, expected);
-    }
-}
diff --git a/src/test/lido/L1LidoGateway.t.sol b/src/test/lido/L1LidoGateway.t.sol
index 5d6b4951..b94ac352 100644
--- a/src/test/lido/L1LidoGateway.t.sol
+++ b/src/test/lido/L1LidoGateway.t.sol
@@ -330,86 +330,6 @@ contract L1LidoGatewayTest is L1GatewayTestBase {
         _depositERC20(true, 2, amount, recipient, dataToCall, gasLimit, feePerGas);
     }
 
-    function testDropMessage(uint256 amount, address recipient) public {
-        hevm.assume(recipient != address(0));
-
-        amount = bound(amount, 1, l1Token.balanceOf(address(this)));
-        bytes memory message = abi.encodeCall(
-            IL2ERC20Gateway.finalizeDepositERC20,
-            (address(l1Token), address(l2Token), address(this), recipient, amount, new bytes(0))
-        );
-        gateway.depositERC20AndCall(address(l1Token), recipient, amount, new bytes(0), defaultGasLimit);
-
-        MockScrollMessenger mockMessenger = new MockScrollMessenger();
-        MockL1LidoGateway mockGateway = _deployGateway(address(mockMessenger));
-        mockGateway.initialize(address(counterpartGateway), address(router), address(mockMessenger));
-        mockGateway.initializeV2(address(0), address(0), address(0), address(0));
-
-        // revert caller is not messenger
-        hevm.expectRevert(ErrorCallerIsNotMessenger.selector);
-        mockGateway.onDropMessage(new bytes(0));
-
-        // revert not in drop context
-        hevm.expectRevert(ErrorNotInDropMessageContext.selector);
-        mockMessenger.callTarget(address(mockGateway), abi.encodeCall(mockGateway.onDropMessage, (new bytes(0))));
-
-        // revert when reentrant
-        mockMessenger.setXDomainMessageSender(ScrollConstants.DROP_XDOMAIN_MESSAGE_SENDER);
-        hevm.expectRevert("ReentrancyGuard: reentrant call");
-        mockGateway.reentrantCall(
-            address(mockMessenger),
-            abi.encodeCall(
-                mockMessenger.callTarget,
-                (address(mockGateway), abi.encodeCall(mockGateway.onDropMessage, (message)))
-            )
-        );
-
-        // revert when invalid selector
-        hevm.expectRevert("invalid selector");
-        mockMessenger.callTarget(address(mockGateway), abi.encodeCall(mockGateway.onDropMessage, (new bytes(4))));
-
-        // revert when l1 token not supported
-        hevm.expectRevert(ErrorUnsupportedL1Token.selector);
-        mockMessenger.callTarget(
-            address(mockGateway),
-            abi.encodeCall(
-                mockGateway.onDropMessage,
-                (
-                    abi.encodeCall(
-                        IL2ERC20Gateway.finalizeDepositERC20,
-                        (address(l2Token), address(l2Token), address(this), recipient, amount, new bytes(0))
-                    )
-                )
-            )
-        );
-
-        // revert when nonzero msg.value
-        hevm.expectRevert(ErrorNonZeroMsgValue.selector);
-        mockMessenger.callTarget{value: 1}(
-            address(mockGateway),
-            abi.encodeWithSelector(mockGateway.onDropMessage.selector, message)
-        );
-
-        // succeed on drop
-        // skip message 0
-        hevm.startPrank(address(rollup));
-        messageQueueV1.popCrossDomainMessage(0, 1, 0x1);
-        messageQueueV1.finalizePoppedCrossDomainMessage(1);
-        assertEq(messageQueueV1.nextUnfinalizedQueueIndex(), 1);
-        assertEq(messageQueueV1.pendingQueueIndex(), 1);
-        hevm.stopPrank();
-
-        // should emit RefundERC20
-        hevm.expectEmit(true, true, false, true);
-        emit RefundERC20(address(l1Token), address(this), amount);
-
-        uint256 balance = l1Token.balanceOf(address(this));
-        uint256 gatewayBalance = l1Token.balanceOf(address(gateway));
-        l1Messenger.dropMessage(address(gateway), address(counterpartGateway), 0, 0, message);
-        assertEq(gatewayBalance - amount, l1Token.balanceOf(address(gateway)));
-        assertEq(balance + amount, l1Token.balanceOf(address(this)));
-    }
-
     function testFinalizeWithdrawERC20(
         address sender,
         uint256 amount,