# Bundler Compatibility Test Suite Announcement Hello everyone in the ERC-4337 community! 2022 has been a great year for Account Abstraction. We have come a long way, from an early idea to multiple implementations from different teams, with numerous established companies as well as new startups betting on ERC-4337 becoming the next big thing for Ethereum! We are happy to announce that the latest revision of ERC-4337, as well as the EntryPoint implementation, has reached "release candidate" status and will be in code freeze, pending results of a scheduled security audit. You can read the full release notes of this version here: https://github.com/eth-infinitism/account-abstraction/releases/tag/v0.4.0 MAJOR ANNOUNCEMENT! We strongly believe the best way to achieve the goals of ERC-4337 is through a [unified network](https://notes.ethereum.org/@yoav/unified-erc-4337-mempool) of bundlers and clients. This is why we are also announcing the Bundler Compatibility Test Suite: https://github.com/eth-infinitism/bundler-spec-tests . This set of tests verifies that different Bundlers are able to communicate properly and defend themselves against DoS attack vectors. The tests verify that compliant Bundlers propagate only valid UserOperations through the mempool, handle signature aggregation correctly, prevent UserOperations from accessing restricted storage slots and opcodes, etc. Non-compliant Bundlers are at risk of being attacked and losing money. We encourage all Bundlers to pass all tests in order to defend themselves against DoS attacks and to remain compatible with the mempool shared by all other ERC-4337 Bundlers. Our team will maintain a list of compatible Bundler implementations and our website will provide links to all the compatible bundlers that pass the tests. The reference implementation of the Bundler that is compliant with the Test Suite has already been finalized and has been published to Dockerhub. This Bundler is not intended for use in production, but rather as a reference to other bundler implementations. You can read the full release notes of this version here: https://github.com/eth-infinitism/bundler/releases/tag/v0.4.0 Thanks to everyone who has been contributing to the ERC-4337 related projects for your great work this year. We are looking forward to continuing the collaboration with all the great projects in the Account Abstraction space and hope to have even more of your feedback and input going forward. Happy holidays, The ERC-4337 team.