Ethereum set for Fusaka upgrade with mainnet launch on Dec 3

Ethereum set for Fusaka upgrade with mainnet launch on Dec 3

Ethereum developers have finalized the rollout schedule for the long-awaited Fusaka upgrade during the All Core Developers Consensus (ACDC) call #165.

The decision sets a clear path for testnet deployments in October and a mainnet activation in early December.

The developers agreed to begin with Holesky on October 1, followed by Sepolia on October 14 and Hoodi on October 28.

If all testing stays on track, the Ethereum mainnet will see Fusaka on December 3. The team will reconfirm exact epoch numbers and timestamps in the coming weeks.

The timeline reflects the community’s determination to close out 2025 with this critical network milestone. Previous delays in testing did not slow the momentum.

Instead, teams addressed bugs on Fusaka Devnet-5 and prepared to move forward with Devnet-6. Shadow forks for each testnet are also on the roadmap to ensure smooth transitions.

Fusaka launch brings Blob capacity focus

One of the headline features of Fusaka lies in its handling of blob capacity. At launch, Fusaka itself introduces no immediate changes.

The expansion arrives through two Blob-Parameter-Only (BPO) hard forks staged after mainnet activation.

In the first week following Fusaka, the network will scale from 6/9 blobs per block to 10/15. The second week pushes this even further, raising blob limits to 14/21.

This progressive adjustment is based on preliminary analysis from Devnet-5, where developers observed system stability during a limited data-gathering window.

While some bugs emerged in client software such as Prysm, fixes are underway. A new release of the ckzg library has already addressed vulnerabilities, and additional updates will follow.

These adjustments ensure Ethereum can handle the higher blob count without risking performance issues.

Ethereum eyes Glamsterdam upgrade on horizon

Client teams will bundle releases for the upcoming testnet activations. Later releases, closer to the December launch, may come independently.

Developers stressed that nothing short of a major setback would change this year-end target. Beyond Fusaka, discussion has already turned toward the Glamsterdam upgrade.

That future step will introduce enshrined proposer-builder separation and block-level access lists, but for now, the priority is clear.

Ethereum’s roadmap is firmly locked on Fusaka, and the community is preparing for one of the year’s most important network events.

The next few months of testing across Holesky, Sepolia, and Hoodi will be decisive. If successful, Ethereum’s mainnet will enter December with Fusaka live and a new blob capacity era already underway.

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