ERC-1155, ERC-6909, or both?

[sscovil]

EVMAuth has, up to this point, been an extension of the ERC-1155 multi-token standard. However, there is a newer ERC-6909 multi-token standard that improves upon ERC-1155 in several ways:

Feature	ERC-1155	ERC-6909
Callbacks	Required for each transfer to contract accounts; must return specific values	Removed entirely; no callbacks required
Batch Operations	Included in specification (batch transfers)	Excluded from specification to allow custom implementations
Permission System	Single operator scheme: operators get unlimited allowance on all token IDs	Hybrid scheme: allowances for specific token IDs + operators for all tokens
Transfer Methods	Both transferFrom and safeTransferFrom required; no opt-out for callbacks	Simplified transfers without mandatory recipient validation
Interface Complexity	Includes multiple features (callbacks, batching, etc.)	Minimized to bare essentials for multi-token management
Recipient Requirements	Contract recipients must implement callback functions with return values	No special requirements for contract recipients
Approval Granularity	Operators only (all-or-nothing for entire contract)	Granular allowances per token ID + full operators

However, as of this writing, EIP-6909 is still under peer review and, as such, has not yet been widely adopted by digital wallet providers.

QUESTION: Should EVMAuth continue to be based on ERC-1155; transition to ERC-6909; or be available in both flavors?

The erc1155-and-erc6909 branch of this repository contains working implementations for both token standards.

In the src/ directory, you will find new ERC1155/ and ERC6909/ directories, both with a file structure like this:

src/
  └── ERCxxxx/
    ├── ERCxxxxAccessControl.sol
    ├── IERCxxxxAccessControl.sol
    └── extensions/
      ├── ERCxxxxBase.sol
      ├── ERCxxxxPrice.sol
      ├── ERCxxxxPurchase.sol
      ├── ERCxxxxPurchaseWithERC20.sol
      ├── ERCxxxxTTL.sol
      ├── IERCxxxxBase.sol
      ├── IERCxxxxPrice.sol
      ├── IERCxxxxPurchase.sol
      ├── IERCxxxxPurchaseWithERC20.sol
      └── IERCxxxxTTL.sol

...and a similar structure in the test/ directory, with 100% test coverage.

This modular structure can be used for EVMAuth or any other multi-token contract. For that reason, I propose we support both token standards and add different deployment scripts for several variants of each (e.g. EVMAuth1155, EVMAuth1155PurchaseWithERC20, EVMAuth6909, EVMAuth1155PurchaseWithERC20).

However, this flexibility comes at a higher cost of maintenance—for both the core contract and the SDKs—and so if we had to choose just one, I would lean toward supporting only ERC-6909.

If you have an opinion on this matter, please let us know!

[Matt-Dionis]

I feel like the best move at this stage is to support both ERC-1155 and ERC-6909, even with the added maintenance efforts.

ERC-6909 looks like the better option overall, but it may take another year or more to see widespread adoption.

[tantodefi]

ya once the erc6909 gets passed/approved and then implementation finalized by open-zeppelin and wallets start supporting then maybe wont need 1155 but for now I'd vote for keeping both to give developers maximum flexibility.

[sscovil]

We'll move forward with support for both token standards, and revisit the matter at a later date to determine if we should deprecate support for ERC-1155.

Thanks all!

[tantodefi]

maybe erc1155 also worth keeping for users who want to use layerzero onft1155 https://docs.layerzero.network/v1/developers/evm/evm-guides/contract-standards/1155