MIP 27: Upgrade Save Contract to comply with ERC-4626

It is proposed to upgrade to our Savings Contracts (imUSD and imBTC) on Ethereum Mainnet and Polygon in order to support the ERC-4626 standard, while still preserving the current functions to allow for backwards compatibility.

The existing Save interface as defined latest in MIP-25 remains intact and ensures backwards compatibility.

A new IERC-4626 interface is used to add functions for being compliant with the standard ERC-4626. This interface is inherited by the SavingsContract. The functions in the SavingsContract that are ERC-4626 compatible map the functionality to existing functions and therefore don’t change the core functionality.

In order to add the functionality to supply a referrer address during deposit, a new ISavingsContractV4 interface has been added to allow the functions to be called in a similar way to the ERC-4626 standard. However, the referrer argument is not part of the ERC-4626 specifications.

Links

• RFC: Upgrade Save Contract to comply with ERC-4626
• Proposal: MIP 27: Upgrade Save Contract to comply with ERC-4626
• Discussion: MIP 27 - Upgrade Save Contract to comply with ERC-4626

Should the imUSD & imBTC Savings Contracts on Ethereum Mainnet and Polygon be upgraded to support the ERC-4626 standard as outlined in MIP 27?