Research & Development

Ethereum’s weekly All Core Developer calls are a lot to keep up with, so this "Checkpoint" series aims for brief high-level updates with a target cadence of every 4-5 calls, depending on what’s happening in core development. See the initial update here. All subsequent updates will be hosted here on the Ethereum Foundation blog. The past month of calls have been focused on Pectra’s testnet upgrades in anticipation of the Pectra mainnet fork with development of the following fork, Fusaka, pushing forward in parallel.

The Pectra testnet activation revealed issues in clients with deposit contract configurations changes on Ethereum testnets. While Sepolia's recovery was straightforward and the network has since fully recovered, Holesky experienced extensive inactivity leaks as part of its recovery mechanism. The Holesky network has since then finalized, but the exited validators would take approximately one year to fully be removed from the validator set (¹). While stakers can test deposits, consolidations and all other Pectra features, the size of the exit queue prevents Holesky from being used to test the full validator lifecycle within a reasonable timeframe. To address this, a new testnet has been launched: Hoodi. It will activate the Pectra network upgrade at epoch 2048 (Wed. March 26, 2025 14:37:12 UTC). Client releases that support the

The Mekong devnet was meant to be a playground for wallet developers to experiment with UX changes and for stakers to gain confidence in the upcoming Pectra changes. The Pectra network upgrade has been activated on the Ethereum Sepolia and Holesky testnets. These networks can now be used to test the Pectra upgrade features. In light of this, we'd like to announce the deprecation of the Mekong testnet on 7th March, 2025. Application and tooling developers are encouraged to use Sepolia to test applications, smart contracts, and other EVM functionality. Its permissioned validator set provides a stable test environment. Alternatively, many local development environments allow for testing against copies of the Ethereum mainnet state. **Stakers and infrastructure providers concerned with protocol-level testing are encouraged to wait for

At 7:29 UTC today, on epoch 222464, the Pectra network upgrade went live on the Sepolia testnet. Unfortunately, an issue with Sepolia's permissioned deposit contract prevented many execution layer clients from including transactions in blocks. The root cause was identified within minutes, and client teams immediately began working on a fix. This issue is due to Sepolia's configuration and could not occur on the Ethereum mainnet. Around 14:00 UTC today, validators deployed a fix that restored the network to normal throughput. All Sepolia node operators must now upgrade their execution layer clients to the versions listed below to maintain network compatibility.

The security of the Ethereum protocol is continually being improved, and one recent effort is the external security review of the Pectra System Contracts. The results of this review can be found in the audits repository, and the TL;DR is that all discovered issues deemed relevant or important from these reviews have been addressed.

Today, we're excited to announce the Pectra Audit Competition, kicking off on Cantina! This month-long event will run from February 21 to March 24, and we're excited to see what issues the security community can find.

tl;dr: Ethereum Protocol Studies is returning for 2025. Visit epf.wiki to fill out the survey and join the town hall on Wednesday, Feb 12. The Ethereum Protocol Studies program (EPS) is back for 2025! Designed to lower the barrier to understanding Ethereum's core protocol, EPS provides structured learning and a direct path to deeper protocol knowledge.