# Ethereum Protocol Fellowship - The Third Cohort (Update 7)

This is the seventh update for Ethereum Protocol Fellowship - The Third Cohort.

In the past two weeks (mainly in the last week due to the winter holidays), I have been working on implementing a private in-memory mempool for user operations (ERC-4337 Account Abstraction). This was something other than planned: the reason for shifting priorities was that this MVP implementation would be helpful for passing the [bundler tests](https://github.com/eth-infinitism/bundler-spec-tests) that were released in the previous week.

- Description: https://github.com/eth-protocol-fellows/cohort-three/blob/master/projects/4337-bundler-rust.md
- Architecture and specification: https://hackmd.io/@Vid201/aa-bundler-rust
- GitHub repository: https://github.com/Vid201/aa-bundler/

## Updates

List of updates:

1. Some cleaning up of the repo: https://github.com/Vid201/aa-bundler/commit/7a72c162ff03f19e750e4204d3b143b8d895a028
2. Sanity checks and simulation of user operations: https://github.com/Vid201/aa-bundler/commit/baad197c9750fa493a87700f333e05d7423c707c
3. First implementation of the in-memory mempool for user operations: https://github.com/Vid201/aa-bundler/pull/34
4. Bundlers working group officially kicked off this week, and one of the goals is to define a p2p protocol for exchanging user operations between bundlers (similar to how standard transactions are propagated between nodes). I started learning about in detail and researching the p2p protocols of Ethereum (https://github.com/ethereum/devp2p, https://ethereum.org/en/developers/docs/networking-layer/).

## Next steps

In the next two weeks, the in-memory mempool will hopefully be merged, and I will be able to finish the first implementation of sanity checks and simulations. My goal is to produce MVP so we can start working on passing the official bundler tests.