Glamsterdam will launch on Sepolia on October 6

The Ethereum Foundation announced that the Glamsterdam network upgrade is scheduled to activate on the Sepolia testnet at 13:53:36 UTC on October 6, corresponding to epoch 353,024 and slot 11,296,768. The timing for Hoodi on the mainnet has not yet been finalized.

This upgrade merges the execution layer Amsterdam with the consensus layer Gloas, following Fusaka. The core of the upgrade is to separate the proposer-builder roles in the protocol (ePBS, EIP-7732) and to implement block-level access lists (BALs, EIP-7928). ePBS allows proposers to include commitments from builders on execution payloads before builders reveal the payloads, reducing reliance on middleware relays. BALs enable clients to read state in parallel and validate transactions. EIP-8037 and EIP-8038 adjust gas pricing to make state creation and access costs more realistic, requiring contracts and wallets to be retested. The scope is tracked by meta EIP-7773.

Clients that support the Sepolia fork include consensus layer Lodestar 1.49.0, Prysm 7.2.0, Teku 26.9.1, and execution layer Besu 26.9.0, Erigon 3.7.0, go-ethereum 1.17.6, Nethermind 2.0.0, Reth 2.7.0. Nodes must upgrade both layers of clients before activation. Prysm 7.2.0 will have a default gas limit of 60 million after activation. Mainnet users and ETH holders do not need to take action. The roadmap for the mainnet still points to Q4 2026, with no specific date. October 6 replaces the previously discussed target of September 28.

Developers warn that Sepolia test ETH is nearly free, and builder identities can be discarded, allowing attackers to repeatedly win block auctions and refuse to submit payloads; this risk does not affect mainnet funds. Devnet-11 has completed the transition to Gloas, raising the gas limit from 60 million to 200 million while maintaining finality. The foundation has also opened Platåberget for applications and infrastructure to test new rules in advance. A consensus layer meeting among core developers verbally discussed Hoodi around October 27, but it has not yet been added to the activation table.

Buyers include client teams, validators, and layer two infrastructure, while sellers are the protocol rules themselves. Funds do not migrate on-chain; costs are incurred from node upgrades and application retesting. Beneficiaries are rollups and block builders that require higher throughput and parallel execution, while those under pressure are wallets, indexers with hard-coded gas limits, and contracts that have not adjusted state pricing. The event driver is the locking of the testnet fork schedule, not the mainnet switch.

Source: Public Information