Research & Development

Ethereum’s weekly All Core Developer calls are a lot to keep up with, so this "Checkpoint" series aims for high-level updates roughly every 4-5 calls, depending on what’s happening in core development. See the previous update here.

The Pectra network upgrade is scheduled to activate on the Ethereum mainnet on May 07, 2025 at epoch 364032 (10:05:11 UTC)! Mainnet client releases are listed below.

TL;DR: Review the program details for EPF6 🔎 Applications for EPF6 are open until April 30 📝 An introductory town hall will be held for an overview and questions on April 21 at 4PM UTC 🎙️ We are excited to announce that the applications are now open for the sixth cohort of the Ethereum Protocol Fellowship (EPF6). The EPF provides a pathway for aspiring protocol developers to make meaningful contributions to Ethereum. In each cohort, a diverse group is assembled to work toward advancing Ethereum's roadmap during the fellowship. This includes the development of client implementations, testing and specifications, and participating in the latest core protocol research. With an overarching goal to find eventual placement for fellows in R&D teams working on core protocol development,

TL;DR: The EPF successfully concluded the fifth cohort, Study Group 2025 and is preparing for cohort six (EPF6). Applications will be announced soon, keep an eye on the EF blog! In the meantime, get ready by enhancing your Ethereum protocol knowledge at EPF.wiki and sign up for the newsletter to get notified about announcements. The Ethereum Protocol Fellowship completed its fifth cohort, culminating with EPF Day at Devcon in Bangkok. Its completion marked 5 months of immersive learning, research and contribution to the Ethereum core ecosystem from a group of talented and dedicated fellows. Client devs and researchers welcomed new contributors, some of which stayed working with them long-term. Additionally, the second iteration of the Protocol Study Group concluded after 2 months of intensive learning about

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.