zkSync contracts v5.1 upgrade announcement

Please note, that the upgrade comes as an amendment of the previous one. And contains all the changes that it had, but brings a lot of new features as well.

This upgrade brings native NFT and atomic swaps/limit orders support. This upgrade requires regenerating the root hash and so requires the most trust from our users, more on that can be read here (opens new window).

Changes

The exact changes in the code of the contracts can be found here (opens new window).

Added

• MintNFT, WithdrawNFT operations, which enable native NFT support. More on the NFT structure can be read here.
• Swap operation, which depending on the implementation may serve either atomic swaps or limit orders functionality. You can read more here.
• The security council, which is able to shorten the upgrade notice period. More on that here (opens new window).
• RegeneisMultisig.sol to handle submissions of the new root hash by the security council during the upgrade.
• A special account with id 2**24 - 1. It is used to ensure the correctness of the NFT data.

Changed

• The maximum amount of tokens that can be used to pay transaction fees is increased to 1023.
• The account tree depth for each account increased to 32.
• Due to the smart contract size limitations, ZkSync.sol was split into two parts: the original ZkSync.sol and the AdditionalZkSync.sol, to which some functionality is delegated.
• ZkSyncNFTFactory.sol which serves as a default NFT factory, where all the NFTs are withdrawn by default.
• Various minor / stylistic fixes.