Ethereum developers will activate the Glamsterdam upgrade on the Hoodi testnet on October 26 at 17:42:48 UTC, raising the network's gas limit from 60 million to 200 million. The schedule was announced by the Ethereum Foundation, whose official blog post sets out the activation.

The Hoodi deployment gives developers a live environment to test changes to transaction processing, block production, and gas costs before a mainnet activation date is chosen. Testnets serve as rehearsal networks where protocol changes can be validated under real network conditions without risk to mainnet funds — a stage that carries extra weight for an upgrade that changes how blocks themselves are built and validated.

Hoodi Activation Follows Sepolia

According to the announcement, Hoodi will trigger Glamsterdam at epoch 132,352, slot 4,235,264. The activation follows Glamsterdam's October 6 deployment on Sepolia, where the network already operates with a 200-million gas limit. Hoodi's limit will rise roughly 3.3 times at the scheduled fork.

The increase applies only to the testnet and does not establish Ethereum's mainnet gas limit. Developers will use the Hoodi deployment to evaluate client compatibility and observe network behavior under the new parameters.

Validators and node operators must update both their execution and consensus clients before activation to stay on the upgraded chain; those who miss the update will remain on the pre-fork version of the testnet chain. Experience from the Sepolia fork underlines the importance of that step: some validator clients retained a default gas target of 60 million, and operators had to adjust the setting manually to propose blocks containing 200 million gas.

ePBS and Block-Level Access Lists Reshape Block Processing

Glamsterdam contains two core changes: enshrined proposer-builder separation, known as ePBS, and block-level access lists, known as BALs. The ePBS mechanism brings the relationship between block proposers and block builders into Ethereum's protocol itself, reducing reliance on external arrangements between the two parties. Enshrining that handoff in consensus rules means the protocol itself, rather than off-chain agreements between participants, governs how a block proposed by one party and built by another fits together.

BALs identify the accounts and storage locations accessed within a block. This information allows clients to process state data and validate transactions in parallel, rather than sequentially — which can shorten how long nodes take to process each block as tested block capacity increases.

Ethereum researcher Toni Wahrstätter has said Hoodi is the final testnet before mainnet. He also suggested that a 300-million gas limit could be a realistic next step, although developers have not confirmed that setting. That makes the October 26 activation the final scheduled testing milestone ahead of any mainnet decision.

Gas Repricing May Affect Existing Tools

Glamsterdam also revises gas pricing for state creation and data access. Replays of historical mainnet transactions identified a small group of contracts whose existing gas assumptions could break under the upgrade.

The Ethereum Foundation's Protocol DevOps team previously warned that tools relying on hardcoded maximum gas limits would need to be updated. Whether tooling providers ship those updates before the Hoodi activation is one practical checkpoint for the fork.

Developers first tested Glamsterdam's gas model on the Plataberget testnet, which launched on August 13. After Sepolia activated the upgrade on October 6, Hoodi became the next scheduled testnet in the rollout sequence.

The Ethereum Foundation has not announced a mainnet activation date, and ETH holders do not need to take any action.