Protocol Announcements

Fusaka follows this year's Pectra upgrade, representing a major step forward in Ethereum's scaling roadmap by introducing PeerDAS and key improvements that enhance blob throughput, L1 performance, and user experience. This post announces the testnet activation schedule for the first three testnets, beginning with Holesky at slot 5,283,840 (October 1, 2025, 08:48:00 UTC). See the activation table below for the complete Sepolia and Hoodi timeline. Fusaka also introduces Blob Parameter Only (BPO) forks to safely scale blob throughput after PeerDAS activation. These are minimal, config-only upgrades that adjust the blob target/max and fee update fraction. The Fusaka testnet client releases are listed below. Once all three testnets have successfully upgraded, a mainnet activation slot will be chosen.

As previously announced, the Holešky testnet has reached its planned end-of-life date and will be sunset shortly. The vast majority of remaining validator nodes will be shut down 2 weeks after the Fusaka upgrade has finalized on Holešky. After this, Holešky will no longer be supported by client, testing or infrastructure teams. Following the launch of the Hoodi testnet in March 2025, infrastructure providers and staking operators have had the opportunity to migrate their testing operations.

As of today, all Ethereum execution clients support partial history expiry in accordance with EIP-4444. While work on full, rolling history expiry is ongoing, users can expect to reduce the disk space required for an Ethereum node by 300-500 GB by removing the block data prior to the Merge. This will allow a node to fit comfortably on a 2 TB disk. See below for information on each specific client.

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.

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.