Ethereum News Today: Ethereum Fusaka Upgrade Delayed for More Testing

Ethereum’s Fusaka upgrade, a major step in the blockchain’s roadmap for improving scalability and data availability, may face a delay in its development timeline, according to recent discussions among core developers. While the upgrade still aims for a November 2025 mainnet deployment, consensus-client teams have requested additional time to finalize release candidates. A recent All Core Devs Consensus (ACDC) call revealed that developers from teams such as Lodestar and Prysm believe the current September 1 deadline is overly aggressive and could risk the stability of the final product [1].

Matthew Keil from Lodestar highlighted that the proposed adjustment would extend the timeline by four weeks, pushing the release candidate date from early September to late September. This shift would allow more time for teams to merge large code branches, resolve conflicts, and conduct stability tests on the code that will eventually go live. The extra time is also seen as critical to reduce the risk of late-stage code merges introducing subtle bugs that prior devnet tests might have missed [1].

Manu Nalepa from Prysm supported the delay, emphasizing the importance of testing private mempool behavior and non-finality scenarios. These tests simulate how the network behaves when validators stop finalizing blocks—such as in the case of outages or mass exits—and how transactions are handled when they are intentionally kept private. Both are crucial for ensuring the upgrade works as intended in real-world conditions [1].

The Fusaka upgrade is expected to bring several key improvements, including PeerDAS, which enhances blob data distribution, and an increase in the maximum blob limit per block from six to nine. It also includes adjustments to target blob counts and new opcodes to improve the Ethereum Virtual Machine’s efficiency. These changes are essential for Ethereum’s long-term scalability, especially for rollups that rely on efficient data availability [1].

The delay could have broader implications beyond the Fusaka fork itself. The upgrade enables the Blob Parameter Updates (BPOs), a mechanism to increase blob capacity without requiring another hard fork. The first three BPOs are tentatively scheduled for mid-December, January, and February, and they are contingent on Fusaka’s successful deployment. If the fork is delayed, the entire scaling schedule could be pushed back [1].

Some developers expressed frustration over how the delay request was introduced, with Tim Beiko, who coordinates core developer calls, noting that earlier asynchronous communication would have been more productive. However, Ansgar Dietrichs from the Ethereum Foundation stressed the importance of allowing teams to voice concerns openly, ensuring that no critical issues are overlooked [1].

Despite the delay in the development timeline, no one has proposed moving the mainnet deployment beyond November 2025. The consensus among developers appears to be that code quality and thorough testing should take precedence over rigid deadlines. The next major step is the launch of Holesky, a long-term testnet, in September. Teams are aiming to complete testnet phases before Ethereum’s Devconnect conference in Buenos Aires from November 17 to 22 [1].

The takeaway from the recent discussions is clear: the Ethereum community is prioritizing stability and correctness over strict adherence to the calendar, reinforcing the project’s commitment to a robust and well-vetted implementation of its upgrades [1].

Source: [1] title: Ethereum’s Fusaka upgrade may face delay

(url: https://blockworks.co/news/ethereum-fusaka-upgrade-delay)