Address.toPayable
: added a helper to convert between address types without having to resort to low-level casting. (#1773)- Facilities to make metatransaction-enabled contracts through the Gas Station Network. (#1844)
Address.isContract
: switched fromextcodesize
toextcodehash
for less gas usage. (#1802)SafeMath
: added custom error messages support forsub
,div
andmod
functions.ERC20
andERC777
updated to throw custom errors on subtraction overflows. (#1828)
SignatureBouncer
has been removed from the library, both to avoid confusions with the GSN Bouncers andGSNBouncerSignature
and because the API was not very clear. (#1879)
ERC1820
: added support for interacting with the ERC1820 registry contract (IERC1820Registry
), as well as base contracts that can be registered as implementers there. (#1677)ERC777
: support for the ERC777 token, which has multiple improvements overERC20
(but is backwards compatible with it) such as built-in burning, a more straightforward permission system, and optional sender and receiver hooks on transfer (mandatory for contracts!). (#1684)- All contracts now have revert reason strings, which give insight into error conditions, and help debug failing transactions. (#1704)
- Reverted the Solidity version bump done in v2.2.0, setting the minimum compiler version to v0.5.0, to prevent unexpected build breakage. Users are encouraged however to stay on top of new compiler releases, which usually include bugfixes. (#1729)
PostDeliveryCrowdsale
: some validations where skipped when paired with other crowdsale flavors, such asAllowanceCrowdsale
, orMintableCrowdsale
andERC20Capped
, which could cause buyers to not be able to claim their purchased tokens. (#1721)ERC20._transfer
: thefrom
argument was allowed to be the zero address, so it was possible to internally trigger a transfer of 0 tokens from the zero address. This address is not a valid destinatary of transfers, nor can it give or receive allowance, so this behavior was inconsistent. It now reverts. (#1752)
ERC20Snapshot
: create snapshots on demand of the token balances and total supply, to later retrieve and e.g. calculate dividends at a past time. (#1617)SafeERC20
:ERC20
contracts with no return value (i.e. that revert on failure) are now supported. (#1655)ERC20
: added internal_approve(address owner, address spender, uint256 value)
, allowing derived contracts to set the allowance of arbitrary accounts. (#1609)ERC20Metadata
: added internal_setTokenURI(string memory tokenURI)
. (#1618)TimedCrowdsale
: added internal_extendTime(uint256 newClosingTime)
as well asTimedCrowdsaleExtended(uint256 prevClosingTime, uint256 newClosingTime)
event allowing to extend the crowdsale, as long as it hasn't already closed.
- Upgraded the minimum compiler version to v0.5.2: this removes many Solidity warnings that were false positives. (#1606)
ECDSA
:recover
no longer accepts malleable signatures (those using upper-range values fors
, or 0/1 forv
). (#1622)ERC721
's transfers are now more gas efficient due to removal of unnecessarySafeMath
calls. (#1610)- Fixed variable shadowing issues. (#1606)
- (minor)
SafeERC20
:safeApprove
wasn't properly checking for a zero allowance when attempting to set a non-zero allowance. (#1647)
TokenMetadata
has been renamed toERC20Metadata
. (#1618)- The library
Counter
has been renamed toCounters
and its API has been improved. See an example inERC721
, lines 17 and 204. (#1610)
- Backported
SafeERC20.safeApprove
bugfix. (#1647)
- Removed most of the test suite from the npm package, except
PublicRole.behavior.js
, which may be useful to users testing their ownRoles
.
- Version bump to avoid conflict in the npm registry.
- Now targeting the 0.5.x line of Solidity compilers. For 0.4.24 support, use version 2.0 of OpenZeppelin.
WhitelistCrowdsale
: a crowdsale where only whitelisted accounts (WhitelistedRole
) can purchase tokens. Adding or removing accounts from the whitelist is done by whitelist admins (WhitelistAdminRole
). Similar to the pre-2.0WhitelistedCrowdsale
. (#1525, #1589)RefundablePostDeliveryCrowdsale
: replacement forRefundableCrowdsale
(deprecated, see below) where tokens are only granted once the crowdsale ends (if it meets its goal). (#1543)PausableCrowdsale
: allows for pausers (PauserRole
) to pause token purchases. Other crowdsale operations (e.g. withdrawals and refunds, if applicable) are not affected. (#832)ERC20
:transferFrom
and_burnFrom
now emitApproval
events, to represent the token's state comprehensively through events. (#1524)ERC721
: added_burn(uint256 tokenId)
, replacing the similar deprecated function (see below). (#1550)ERC721
: added_tokensOfOwner(address owner)
, allowing to internally retrieve the array of an account's owned tokens. (#1522)- Crowdsales: all constructors are now
public
, meaning it is not necessary to extend these contracts in order to deploy them. The exception isFinalizableCrowdsale
, since it is meaningless unless extended. (#1564) SignedSafeMath
: added overflow-safe operations for signed integers (int256
). (#1559, #1588)
- The compiler version required by
Array
was behind the rest of the libray so it was updated tov0.4.24
. (#1553) - Now conforming to a 4-space indentation code style. (1508)
ERC20
: more gas efficient due to removed redundantrequire
s. (#1409)ERC721
: fixed a bug that prevented internal data structures from being properly cleaned, missing potential gas refunds. (#1539 and #1549)ERC721
: general gas savings ontransferFrom
,_mint
and_burn
, due to redudantrequire
s andSSTORE
s. (#1549)