Ethereum's Glamsterdam upgrade is scheduled to activate on the Hoodi test network on October 26, 2026, at 17:42:48 UTC. The test pairs changes to block production and validation with a scheduled 200 million gas target. The Ethereum Foundation announced the deployment on October 16, following Glamsterdam's October 6 activation on Sepolia. Mainnet activation timing remains undecided. ETH holders and mainnet operators have no action to take because of the Hoodi announcement.
All Hoodi operators must update execution and consensus clients before activation. Validators must update both the beacon node and validator client. Validators must also review new duties, builder-tooling compatibility and gas-limit settings to follow the upgraded test network.
Ethrex's version listed by the Foundation was a release candidate as checked on October 17. Grandine, Lighthouse, Erigon, go-ethereum and Reth remained unlisted. Operators should use releases whose notes confirm support for this Hoodi activation. Besu 26.10.0 migrates Bonsai code storage on first startup and retains more history when pruning. Downgrading requires the documented besu storage revert-code-format command before an older version can reopen the database.
Hoodi's 200 million gas target is a planned budget for computational work per block. The gas-limit schedule sets client defaults and recommendations while preserving operator preferences. The actual block limit adjusts gradually under existing rules, so the target is not an immediately enforced ceiling. Throughput depends on transaction complexity. Fees also depend on demand.
Glamsterdam combines Amsterdam on the execution layer with Gloas on the consensus layer. Enshrined proposer-builder separation moves the exchange between block proposers and builders into the protocol and gives validators more time to check execution. Block-level access lists record accessed accounts, storage and state changes so clients can perform more work in parallel.
Changed gas pricing can affect contracts that rely on fixed stipends, hardcoded limits or remaining-gas assumptions. The Ethereum Foundation advises developers to test contracts and gas estimation under the new rules.