Ethereum Fusaka upgrade tentatively set for Dec. 3 mainnet launch after testnet rollouts

Ethereum core developers announced plans to launch the Fusaka upgrade on the mainnet on Dec. 3. 

This tentative date was announced in the latest ACDC #165 developer call . 

The upgrade will be activated on the Holesky testnet on Oct. 1, the Sepolia testnet on Oct. 14, and the Hoodi testnet on Oct. 28 before its final mainnet launch. Kim added that developers will reconfirm exact dates, times and epoch numbers in the next few days. 

Developers are expecting blob capacity is to double in the two weeks after the upgrade is activated.

Fusaka is Ethereum’s next major hard fork, aiming to advance the network's scalability while maintaining decentralization and security. 

As one of its main features, Fusaka introduces Peer Data Availability Sampling, which enables validators to verify large datasets, known as blobs, by sampling small portions from peer nodes instead of downloading entire datasets. 

The upgrade also incorporates proposals to increase the block gas limit from 30 million to 150 million units, to support more transactions. Additionally, it includes the implementation of Verkle Trees to optimize data storage for smaller proof sizes, as well as improvements to EVM performance for faster smart contract execution. 

Earlier this week, the Ethereum Foundation launched a four-week audit contest for Fusaka, offering up to $2 million in rewards for security researchers who uncover bugs before the hard fork reaches mainnet.

Following the Fusaka upgrade, Ethereum's next major upgrade is expected to be Glamsterdam in 2026, which will likely focus on further scalability enhancements like the full EVM Object Format (EOF) and faster block times.