@openzeppelin/contracts - npm Package Versions

4.1.0 (2021-04-29)

• IERC20Metadata: add a new extended interface that includes the optional name(), symbol() and decimals() functions. (#2561)
• ERC777: make reception acquirement optional in _mint. (#2552)
• ERC20Permit: add a _useNonce to enable further usage of ERC712 signatures. (#2565)
• ERC20FlashMint: add an implementation of the ERC3156 extension for flash-minting ERC20 tokens. (#2543)
• SignatureChecker: add a signature verification library that supports both EOA and ERC1271 compliant contracts as signers. (#2532)
• Multicall: add abstract contract with multicall(bytes[] calldata data) function to bundle multiple calls together (#2608)
• ECDSA: add support for ERC2098 short-signatures. (#2582)
• AccessControl: add an onlyRole modifier to restrict specific function to callers bearing a specific role. (#2609)
• StorageSlot: add a library for reading and writing primitive types to specific storage slots. (#2542)
• UUPS Proxies: add UUPSUpgradeable to implement the UUPS proxy pattern together with EIP1967Proxy. (#2542)

Breaking changes

This release includes two small breaking changes in TimelockController.

1. The onlyRole modifier in this contract was designed to let anyone through if the role was granted to address(0), allowing the possibility to make a role "open", which can be used for EXECUTOR_ROLE. This modifier is now replaced by AccessControl.onlyRole, which does not have this ability. The previous behavior was moved to the modifier TimelockController.onlyRoleOrOpenRole.
2. It was possible to make PROPOSER_ROLE an open role (as described in the previous item) if it was granted to address(0). This would affect the schedule, scheduleBatch, and cancel operations in TimelockController. This ability was removed as it does not make sense to open up the PROPOSER_ROLE in the same way that it does for EXECUTOR_ROLE.

4.0.0 (2021-03-23)

• Now targeting the 0.8.x line of Solidity compilers. For 0.6.x (resp 0.7.x) support, use version 3.4.0 (resp 3.4.0-solc-0.7) of OpenZeppelin.
• Context: making _msgData return bytes calldata instead of bytes memory (#2492)
• ERC20: removed the _setDecimals function and the storage slot associated to decimals. (#2502)
• Strings: addition of a toHexString function. (#2504)
• EnumerableMap: change implementation to optimize for key → value lookups instead of enumeration. (#2518)
• GSN: deprecate GSNv1 support in favor of upcoming support for GSNv2. (#2521)
• ERC165: remove uses of storage in the base ERC165 implementation. ERC165 based contracts now use storage-less virtual functions. Old behavior remains available in the ERC165Storage extension. (#2505)
• Initializable: make initializer check stricter during construction. (#2531)
• ERC721: remove enumerability of tokens from the base implementation. This feature is now provided separately through the ERC721Enumerable extension. (#2511)
• AccessControl: removed enumerability by default for a more lightweight contract. It is now opt-in through AccessControlEnumerable. (#2512)
• Meta Transactions: add ERC2771Context and a MinimalForwarder for meta-transactions. (#2508)
• Overall reorganization of the contract folder to improve clarity and discoverability. (#2503)
• ERC20Capped: optimize gas usage by enforcing the check directly in _mint. (#2524)
• Rename UpgradeableProxy to ERC1967Proxy. (#2547)
• ERC777: optimize the gas costs of the constructor. (#2551)
• ERC721URIStorage: add a new extension that implements the _setTokenURI behavior as it was available in 3.4.0. (#2555)
• AccessControl: added ERC165 interface detection. (#2562)
• ERC1155: make uri public so overloading function can call it using super. (#2576)

Bug fixes for beta releases

• AccessControlEnumerable: Fixed renounceRole not updating enumerable set of addresses for a role. (#2572)

How to upgrade from 3.x

Since this version has moved a few contracts to different directories, users upgrading from a previous version will need to adjust their import statements. To make this easier, the package includes a script that will migrate import statements automatically. After upgrading to the latest version of the package, run:

npx openzeppelin-contracts-migrate-imports

Make sure you're using git or another version control system to be able to recover from any potential error in our script.

3.4.1 (2021-03-03)

• ERC721: made _approve an internal function (was private).