# Week 12 & 13 Update Hi there, in [my pr](https://github.com/ChainSafe/lodestar/pull/8035) on ERA file reading and writing I added a test which ingests era files generated from Nimbus using https://mainnet.era.nimbus.team/ and then it outputs an era file that is generated by lodestar and it then subsequently reads it using lodestar thus completing a loop which validates my code for era Reading and writing. After some discussion with Mario Havel and my mentor , I decided to work on the [ssz implementation zig ⚡ from Chainsafe](https://github.com/ChainSafe/ssz-z). I picked up [this issue](https://github.com/ChainSafe/ssz-z/issues/32) and I started working on [EIP-7916: SSZ ProgressiveList](https://eips.ethereum.org/EIPS/eip-7916). I went through the [ssz section from epf wiki](https://epf.wiki/#/wiki/CL/SSZ) to revise a bit about ssz. I also found this amazing [tracker](https://pureth.guide/implementations-ssz/) by [Etan from Nimbus](https://github.com/etan-status) to track the [ssz types](https://github.com/ethereum/EIPs/blob/master/EIPS/eip-7919.md#simple-serialize-ssz-requirements) needed for [Pureth Proposal](https://github.com/ethereum/EIPs/blob/master/EIPS/eip-7919.md). I also joined the zig roadmap discussions for Lodestar, a summary of the same can be found [here](https://github.com/ChainSafe/lodestar/wiki/Lodestar-Zig-Roadmap-Discussions#lodestar-zig-roadmap-discussions-3--setepmber-4-2025). Caymen is working on the different db bindings for future lodestar using zig and we can the benchmarks [here](https://github.com/ChainSafe/lodestar-bun/pull/5). This along with ssz library in zig will be a significant boost to Era performance in Lodestar in the coming months. I have pushed a [pr](https://github.com/ChainSafe/ssz-z/pull/64) on Progressive Lists , it passes the CI/CD but I will be adding more test cases. I also fixed the CI/CD with a very small [one-liner pr](https://github.com/ChainSafe/ssz-z/pull/63). ## Work for the next week - I will be adding more tests for Progressive List and complete Progressive BitList - Start working on [Progressive Container](https://eips.ethereum.org/EIPS/eip-7495)