v5.1.0

Breaking changes

• ERC1967Utils: Removed duplicate declaration of the Upgraded, AdminChanged and BeaconUpgraded events. These events are still available through the IERC1967 interface located under the contracts/interfaces/ directory. Minimum pragma version is now 0.8.21.
• Governor, GovernorCountingSimple: The _countVote virtual function now returns an uint256 with the total votes casted. This change allows for more flexibility for partial and fractional voting. Upgrading users may get a compilation error that can be fixed by adding a return statement to the _countVote function.

Custom error changes

This version comes with changes to the custom error identifiers. Contracts previously depending on the following errors should be replaced accordingly:

• Replace Address.FailedInnerCall with Errors.FailedCall
• Replace Address.AddressInsufficientBalance with Errors.InsufficientBalance
• Replace Clones.Create2InsufficientBalance with Errors.InsufficientBalance
• Replace Clones.ERC1167FailedCreateClone with Errors.FailedDeployment
• Replace Clones.Create2FailedDeployment with Errors.FailedDeployment
• SafeERC20: Replace Address.AddressEmptyCode with SafeERC20FailedOperation if there is no code at the token's address.
• SafeERC20: Replace generic Error(string) with SafeERC20FailedOperation if the returned data can't be decoded as bool.
• SafeERC20: Replace generic SafeERC20FailedOperation with the revert message from the contract call if it fails.

Changes by category

General

• AccessManager, VestingWallet, TimelockController and ERC2771Forwarder: Added a public initializer function in their corresponding upgradeable variants. (#5008)

Access

• AccessControlEnumerable: Add a getRoleMembers method to return all accounts that have role. (#4546)
• AccessManager: Allow the onlyAuthorized modifier to restrict functions added to the manager. (#5014)

Finance

• VestingWalletCliff: Add an extension of the VestingWallet contract with an added cliff. (#4870)

Governance

• GovernorCountingFractional: Add a governor counting module that allows distributing voting power amongst 3 options (For, Against, Abstain). (#5045)
• Votes: Set _moveDelegateVotes visibility to internal instead of private. (#5007)

Proxy

• Clones: Add version of clone and cloneDeterministic that support sending value at creation. (#4936)
• TransparentUpgradeableProxy: Make internal _proxyAdmin() getter have view visibility. (#4688)
• ProxyAdmin: Fixed documentation for UPGRADE_INTERFACE_VERSION getter. (#5031)

Tokens

• ERC1363: Add implementation of the token payable standard allowing execution of contract code after transfers and approvals. (#4631)
• ERC20TemporaryApproval: Add an ERC-20 extension that implements temporary approval using transient storage, based on ERC7674 (draft). (#5071)
• SafeERC20: Add "relaxed" function for interacting with ERC-1363 functions in a way that is compatible with EOAs. (#4631)
• SafeERC20: Document risks of safeIncreaseAllowance and safeDecreaseAllowance when associated with ERC-7674. (#5262)
• ERC721Utils and ERC1155Utils: Add reusable libraries with functions to perform acceptance checks on IERC721Receiver and IERC1155Receiver implementers. (#4845)
• ERC1363Utils: Add helper similar to the existing ERC721Utils and ERC1155Utils. (#5133)

Utils

• Arrays: add a sort functions for address[], bytes32[] and uint256[] memory arrays. (#4846)
• Arrays: add new functions lowerBound, upperBound, lowerBoundMemory and upperBoundMemory for lookups in sorted arrays with potential duplicates. (#4842)
• Arrays: deprecate findUpperBound in favor of the new lowerBound. (#4842)
• Base64: Add encodeURL following section 5 of RFC4648 for URL encoding (#4822)
• Comparator: A library of comparator functions, useful for customizing the behavior of the Heap structure. (#5084)
• Create2: Bubbles up returndata from a deployed contract that reverted during construction. (#5052)
• Create2, Clones: Mask computeAddress and cloneDeterministic outputs to produce a clean value for an address type (i.e. only use 20 bytes) (#4941)
• Errors: New library of common custom errors. (#4936)
• Hashes: A library with commonly used hash functions. (#3617)
• Packing: Added a new utility for packing, extracting and replacing bytesXX values. (#4992)
• Panic: Add a library for reverting with panic codes. (#3298)
• ReentrancyGuardTransient: Added a variant of ReentrancyGuard that uses transient storage. (#4988)
• Strings: Added a utility function for converting an address to checksummed string. (#5067)
• SlotDerivation: Add a library of methods for derivating common storage slots. (#4975)
• TransientSlot: Add primitives for operating on the transient storage space using a typed-slot representation. (#4980)

Cryptography

• SignatureChecker: refactor isValidSignatureNow to avoid validating ECDSA signatures if there is code deployed at the signer's address. (#4951)
• MerkleProof: Add variations of verify, processProof, multiProofVerify and processMultiProof (and equivalent calldata version) with support for custom hashing functions. (#4887)
• P256: Library for verification and public key recovery of P256 (aka secp256r1) signatures. (#4881)
• RSA: Library to verify signatures according to RFC 8017 Signature Verification Operation (#4952)

Math

• Math: add an invMod function to get the modular multiplicative inverse of a number in Z/nZ. (#4839)
• Math: Add modExp function that exposes the EIP-198 precompile. Includes uint256 and bytes memory versions. (#3298)
• Math: Custom errors replaced with native panic codes. (#3298)
• Math, SignedMath: Add a branchless ternary function that computescond ? a : b in constant gas cost. (#4976)
• SafeCast: Add toUint(bool) for operating on bool values as uint256. (#4878)

Structures

• CircularBuffer: Add a data structure that stores the last N values pushed to it. (#4913)
• DoubleEndedQueue: Custom errors replaced with native panic codes. (#4872)
• EnumerableMap: add UintToBytes32Map, AddressToAddressMap, AddressToBytes32Map and Bytes32ToAddressMap. (#4843)
• Heap: A data structure that implements a heap-based priority queue. (#5084)
• MerkleTree: A data structure that allows inserting elements into a merkle tree and updating its root hash. (#3617)

v5.1.0-rc.0

Breaking changes

• ERC1967Utils: Removed duplicate declaration of the Upgraded, AdminChanged and BeaconUpgraded events. These events are still available through the IERC1967 interface located under the contracts/interfaces/ directory. Minimum pragma version is now 0.8.21.
• Governor, GovernorCountingSimple: The _countVotes virtual function now returns an uint256 with the total votes casted. This change allows for more flexibility for partial and fractional voting. Upgrading users may get a compilation error that can be fixed by adding a return statement to the _countVotes function.

Custom error changes

This version comes with changes to the custom error identifiers. Contracts previously depending on the following errors should be replaced accordingly:

• Replace Address.FailedInnerCall with Errors.FailedCall
• Replace Address.AddressInsufficientBalance with Errors.InsufficientBalance
• Replace Clones.Create2InsufficientBalance with Errors.InsufficientBalance
• Replace Clones.ERC1167FailedCreateClone with Errors.FailedDeployment
• Replace Clones.Create2FailedDeployment with Errors.FailedDeployment
• SafeERC20: Replace Address.AddressEmptyCode with SafeERC20FailedOperation if there is no code at the token's address.
• SafeERC20: Replace generic Error(string) with SafeERC20FailedOperation if the returned data can't be decoded as bool.
• SafeERC20: Replace generic SafeERC20FailedOperation with the revert message from the contract call if it fails.

Changes by category

General

• AccessManager, VestingWallet, TimelockController and ERC2771Forwarder: Added a public initializer function in their corresponding upgradeable variants. (#5008)

Access

• AccessControlEnumerable: Add a getRoleMembers method to return all accounts that have role. (#4546)
• AccessManager: Allow the onlyAuthorized modifier to restrict functions added to the manager. (#5014)

Finance

• VestingWalletCliff: Add an extension of the VestingWallet contract with an added cliff. (#4870)

Governance

• GovernorCountingFractional: Add a governor counting module that allows distributing voting power amongst 3 options (For, Against, Abstain). (#5045)
• Votes: Set _moveDelegateVotes visibility to internal instead of private. (#5007)

Proxy

• Clones: Add version of clone and cloneDeterministic that support sending value at creation. (#4936)
• TransparentUpgradeableProxy: Make internal _proxyAdmin() getter have view visibility. (#4688)
• ProxyAdmin: Fixed documentation for UPGRADE_INTERFACE_VERSION getter. (#5031)

Tokens

• ERC1363: Add implementation of the token payable standard allowing execution of contract code after transfers and approvals. (#4631)
• ERC20TemporaryApproval: Add an ERC-20 extension that implements temporary approval using transient storage, based on ERC7674 (draft). (#5071)
• SafeERC20: Add "relaxed" function for interacting with ERC-1363 functions in a way that is compatible with EOAs. (#4631)
• ERC721Utils and ERC1155Utils: Add reusable libraries with functions to perform acceptance checks on IERC721Receiver and IERC1155Receiver implementers. (#4845)
• ERC1363Utils: Add helper similar to the existing ERC721Utils and ERC1155Utils. (#5133)

Utils

• Arrays: add a sort functions for address[], bytes32[] and uint256[] memory arrays. (#4846)
• Arrays: add new functions lowerBound, upperBound, lowerBoundMemory and upperBoundMemory for lookups in sorted arrays with potential duplicates. (#4842)
• Arrays: deprecate findUpperBound in favor of the new lowerBound. (#4842)
• Base64: Add encodeURL following section 5 of RFC4648 for URL encoding (#4822)
• Comparator: A library of comparator functions, useful for customizing the behavior of the Heap structure. (#5084)
• Create2: Bubbles up returndata from a deployed contract that reverted during construction. (#5052)
• Create2, Clones: Mask computeAddress and cloneDeterministic outputs to produce a clean value for an address type (i.e. only use 20 bytes) (#4941)
• Errors: New library of common custom errors. (#4936)
• Hashes: A library with commonly used hash functions. (#3617)
• Packing: Added a new utility for packing, extracting and replacing bytesXX values. (#4992)
• Panic: Add a library for reverting with panic codes. (#3298)
• ReentrancyGuardTransient: Added a variant of ReentrancyGuard that uses transient storage. (#4988)
• Strings: Added a utility function for converting an address to checksummed string. (#5067)
• SlotDerivation: Add a library of methods for derivating common storage slots. (#4975)
• StorageSlot: Add primitives for operating on the transient storage space using a typed-slot representation. (#4980)

Cryptography

• SignatureChecker: refactor isValidSignatureNow to avoid validating ECDSA signatures if there is code deployed at the signer's address. (#4951)
• MerkleProof: Add variations of verify, processProof, multiProofVerify and processMultiProof (and equivalent calldata version) with support for custom hashing functions. (#4887)
• P256: Library for verification and public key recovery of P256 (aka secp256r1) signatures. (#4881)
• RSA: Library to verify signatures according to RFC 8017 Signature Verification Operation (#4952)

Math

• Math: add an invMod function to get the modular multiplicative inverse of a number in Z/nZ. (#4839)
• Math: Add modExp function that exposes the EIP-198 precompile. Includes uint256 and bytes memory versions. (#3298)
• Math: Custom errors replaced with native panic codes. (#3298)
• Math, SignedMath: Add a branchless ternary function that computescond ? a : b in constant gas cost. (#4976)
• SafeCast: Add toUint(bool) for operating on bool values as uint256. (#4878)

Structures

• CircularBuffer: Add a data structure that stores the last N values pushed to it. (#4913)
• DoubleEndedQueue: Custom errors replaced with native panic codes. (#4872)
• EnumerableMap: add UintToBytes32Map, AddressToAddressMap, AddressToBytes32Map and Bytes32ToAddressMap. (#4843)
• Heap: A data structure that implements a heap-based priority queue. (#5084)
• MerkleTree: A data structure that allows inserting elements into a merkle tree and updating its root hash. (#3617)

v5.0.2

• Base64: Fix issue where dirty memory located just after the input buffer is affecting the result. (#4926)

v4.9.6

• Base64: Fix issue where dirty memory located just after the input buffer is affecting the result. (#4929)

v4.9.5

• Multicall: Make aware of non-canonical context (i.e. msg.sender is not _msgSender()), allowing compatibility with ERC2771Context. Patch duplicated Address.functionDelegateCall in v4.9.4 (removed).

v5.0.1

• ERC2771Context and Context: Introduce a _contextPrefixLength() getter, used to trim extra information appended to msg.data.
• Multicall: Make aware of non-canonical context (i.e. msg.sender is not _msgSender()), allowing compatibility with ERC2771Context.

v4.9.4

• ERC2771Context and Context: Introduce a _contextPrefixLength() getter, used to trim extra information appended to msg.data.
• Multicall: Make aware of non-canonical context (i.e. msg.sender is not _msgSender()), allowing compatibility with ERC2771Context.

v5.0.0

Additions Summary

The following contracts and libraries were added:

• AccessManager: A consolidated system for managing access control in complex systems.
  • AccessManaged: A module for connecting a contract to an authority in charge of its access control.
  • GovernorTimelockAccess: An adapter for time-locking governance proposals using an AccessManager.
  • AuthorityUtils: A library of utilities for interacting with authority contracts.
• GovernorStorage: A Governor module that stores proposal details in storage.
• ERC2771Forwarder: An ERC2771 forwarder for meta transactions.
• ERC1967Utils: A library with ERC1967 events, errors and getters.
• Nonces: An abstraction for managing account nonces.
• MessageHashUtils: A library for producing digests for ECDSA operations.
• Time: A library with helpers for manipulating time-related objects.

Removals Summary

The following contracts, libraries, and functions were removed:

• Address.isContract (because of its ambiguous nature and potential for misuse)
• Checkpoints.History
• Counters
• ERC20Snapshot
• ERC20VotesComp
• ERC165Storage (in favor of inheritance based approach)
• ERC777
• ERC1820Implementer
• GovernorVotesComp
• GovernorProposalThreshold (deprecated since 4.4)
• PaymentSplitter
• PullPayment
• SafeMath
• SignedSafeMath
• Timers
• TokenTimelock (in favor of VestingWallet)
• All escrow contracts (Escrow, ConditionalEscrow and RefundEscrow)
• All cross-chain contracts, including AccessControlCrossChain and all the vendored bridge interfaces
• All presets in favor of OpenZeppelin Contracts Wizard

These removals were implemented in the following PRs: #3637, #3880, #3945, #4258, #4276, #4289

Changes by category

General

• Replaced revert strings and require statements with custom errors. (#4261)
• Bumped minimum compiler version required to 0.8.20 (#4288)
• Use of abi.encodeCall in place of abi.encodeWithSelector and abi.encodeWithSignature for improved type-checking of parameters (#4293)
• Replaced some uses of abi.encodePacked with clearer alternatives (e.g. bytes.concat, string.concat). (#4504) (#4296)
• Overrides are now used internally for a number of functions that were previously hardcoded to their default implementation in certain locations: ERC1155Supply.totalSupply, ERC721.ownerOf, ERC721.balanceOf and ERC721.totalSupply in ERC721Enumerable, ERC20.totalSupply in ERC20FlashMint, and ERC1967._getImplementation in ERC1967Proxy. (#4299)
• Removed the override specifier from functions that only override a single interface function. (#4315)
• Switched to using explicit Solidity import statements. Some previously available symbols may now have to be separately imported. (#4399)
• Governor, Initializable, and UUPSUpgradeable: Use internal functions in modifiers to optimize bytecode size. (#4472)
• Upgradeable contracts now use namespaced storage (EIP-7201). (#4534)
• Upgradeable contracts no longer transpile interfaces and libraries. (#4628)

Access

• Ownable: Added an initialOwner parameter to the constructor, making the ownership initialization explicit. (#4267)
• Ownable: Prevent using address(0) as the initial owner. (#4531)
• AccessControl: Added a boolean return value to the internal _grantRole and _revokeRole functions indicating whether the role was granted or revoked. (#4241)
• access: Moved AccessControl extensions to a dedicated directory. (#4359)
• AccessManager: Added a new contract for managing access control of complex systems in a consolidated location. (#4121)
• AccessManager, AccessManaged, GovernorTimelockAccess: Ensure that calldata shorter than 4 bytes is not padded to 4 bytes. (#4624)
• AccessManager: Use named return parameters in functions that return multiple values. (#4624)
• AccessManager: Make schedule and execute more conservative when delay is 0. (#4644)

Finance

• VestingWallet: Fixed revert during 1 second time window when duration is 0. (#4502)
• VestingWallet: Use Ownable instead of an immutable beneficiary. (#4508)

Governance

• Governor: Optimized use of storage for proposal data (#4268)
• Governor: Added validation in ERC1155 and ERC721 receiver hooks to ensure Governor is the executor. (#4314)
• Governor: Refactored internals to implement common queuing logic in the core module of the Governor. Added queue and _queueOperations functions that act at different levels. Modules that implement queuing via timelocks are expected to override _queueOperations to implement the timelock-specific logic. Added _executeOperations as the equivalent for execution. (#4360)
• Governor: Added voter and nonce parameters in signed ballots, to avoid forging signatures for random addresses, prevent signature replay, and allow invalidating signatures. Add voter as a new parameter in the castVoteBySig and castVoteWithReasonAndParamsBySig functions. (#4378)
• Governor: Added support for casting votes with ERC-1271 signatures by using a bytes memory signature instead of r, s and v arguments in the castVoteBySig and castVoteWithReasonAndParamsBySig functions. (#4418)
• Governor: Added a mechanism to restrict the address of the proposer using a suffix in the description.
• GovernorStorage: Added a new governor extension that stores the proposal details in storage, with an interface that operates on proposalId, as well as proposal enumerability. This replaces the old GovernorCompatibilityBravo module. (#4360)
• GovernorTimelockAccess: Added a module to connect a governor with an instance of AccessManager, allowing the governor to make calls that are delay-restricted by the manager using the normal queue workflow. (#4523)
• GovernorTimelockControl: Clean up timelock id on execution for gas refund. (#4118)
• GovernorTimelockControl: Added the Governor instance address as part of the TimelockController operation salt to avoid operation id collisions between governors using the same TimelockController. (#4432)
• TimelockController: Changed the role architecture to use DEFAULT_ADMIN_ROLE as the admin for all roles, instead of the bespoke TIMELOCK_ADMIN_ROLE that was used previously. This aligns with the general recommendation for AccessControl and makes the addition of new roles easier. Accordingly, the admin parameter and timelock will now be granted DEFAULT_ADMIN_ROLE instead of TIMELOCK_ADMIN_ROLE. (#3799)
• TimelockController: Added a state getter that returns an OperationState enum. (#4358)
• Votes: Use Trace208 for checkpoints. This enables EIP-6372 clock support for keys but reduces the max supported voting power to uint208. (#4539)

Metatx

• ERC2771Forwarder: Added deadline for expiring transactions, batching, and more secure handling of msg.value. (#4346)
• ERC2771Context: Return the forwarder address whenever the msg.data of a call originating from a trusted forwarder is not long enough to contain the request signer address (i.e. msg.data.length is less than 20 bytes), as...

v5.0.0-rc.2

• AccessManager: Make schedule and execute more conservative when delay is 0.

v5.0.0-rc.1

• Upgradeable Contracts: No longer transpile interfaces, libraries, and stateless contracts. (#4636)
• AccessManager, AccessManaged, GovernorTimelockAccess: Ensure that calldata shorter than 4 bytes is not padded to 4 bytes. (#4624)
• AccessManager: Use named return parameters in functions that return multiple values. (#4624)