# EPF week 4

This week, I was on vacation, so I wasn’t able to contribute to any technical or coding tasks directly. However, I focused on coordination and planning activities to ensure ongoing progress on the project.

One of the main efforts this week was around organizing support for the Pureth implementation on the Nimbus EL side. While Etan, the original author of Pureth, primarily works on Nimbus CL, we needed someone from the EL team who could assist with integrating or adapting Pureth into Nimbus EL.

After discussions with my mentor and the broader team, we finalized and onboarded Advaita from the Nimbus EL team to support this effort.
This coordination step was crucial in ensuring that we have the right technical mentorship and support on the EL side as we move forward with the Pureth-related development work.

Here’s a clearer and more professional rewording of your FOCIL updates section:

## FOCIL Updates

Had an in-depth discussion with my collaborator, ZKash, regarding the division of responsibilities for the FOCIL implementation.

We finalized the structure of our collaboration:

* **ZKash** will focus on implementing the **P2P modifications** and the **Fork-Choice rule changes**.
* **(RazorClients)** will handle the **Engine API updates** and **Validator-related changes**.

* We’ve aligned on a tentative timeline: within a maximum span of **4 weeks (1 month)**, both of us aim to complete our respective components.

* Once this initial development phase is complete, we’ll begin **testing the FOCIL-enabled CL in real scenarios**, integrating it with **Prysm (CL)** and **Nethermind/Geth (EL)** implementations.

* Following successful integration testing, we plan to move ahead with **deployment on a local interop testnet** to validate the full end-to-end functionality.

Here’s a refined and expanded version of your update for the **Pureth** section, with improved clarity, grammar, and structure:

## Pureth

We had originally planned to present the Pureth idea during Week 4 office hours. However, in the interest of more thorough planning and clearer understanding, we decided to postpone the presentation to **Week 5 office hours**.

During our initial review, we encountered confusion around the [Pureth website](https://purified-web3.box/). We weren’t able to verify the accuracy or relevance of its contents. After consulting with Etan, we learned that the site reflects an **outdated version** of the Pureth spec and refers to **Nimbus CL**, not **Nimbus EL**, which led to some early misdirection.

### Pureth Breakdown

Pureth can essentially be divided into several key components based on the changes proposed in [EIP-7919](https://eips.ethereum.org/EIPS/eip-7919):

* **SSZ Changes:**

* General SSZ requirements: [EIP-7919 ssz-requirements](https://eips.ethereum.org/EIPS/eip-7919#simple-serialize-ssz-requirements)
* Serialization harmonization and removal of old tx types:

* [EIP-7919 serialization-harmonization](https://eips.ethereum.org/EIPS/eip-7919#purge-serialization-harmonization)
* [EIP-7919 remove-old-tx-types](https://eips.ethereum.org/EIPS/eip-7919purge-remove-old-tx-types)

* **Log Changes:**

* Reforming the logging structure: [EIP-7919 log-reform](https://eips.ethereum.org/EIPS/eip-7919#purge-log-reform)

### Work Division

After discussions with **Vineet**, my collaborator on this project, we decided to split the work as follows:

* **Vineet** will be responsible for the **log-related changes**, focusing primarily on:

* **2D logs** [EIP-7745](https://eips.ethereum.org/EIPS/eip-7745) (log reform and compression strategies)

* **RazorClients** will be handling the **SSZ-related changes**, with a focus on:

* [EIP-6404](https://eips.ethereum.org/EIPS/eip-6404) — defining a fixed SSZ schema for execution payloads.

* The ssz requirement for nim are being worked upon by **Etan** and he also plans on bumping the nimbus cl to help us keep working on the el side of things

A more detailed project breakdown and execution plan will be included in the updated proposal, which we’ll present during this week’s office hours.

Overall, while there was no hands-on development from my side this week, the planning and coordination efforts were productive in setting up the next phase of implementation.