Ethereum has scheduled the Glamsterdam upgrade for Hoodi, a test network, on October 26, 2026, at 17:42:48 UTC. The activation creates a software deadline for testnet operators and pairs changes to block production and validation with a 200 million gas target.
The Ethereum Foundation announced the date on October 16, following Glamsterdam's October 6 activation on the Sepolia testnet. Mainnet timing for this upgrade remains undecided. ETH holders and mainnet operators are not affected by this testnet announcement.
Required software updates
All Hoodi operators must update their execution and consensus clients before the October 26 deadline. Validators must upgrade both their beacon node and validator client, and review new duties, builder-tooling compatibility, and gas-limit settings.
The Foundation confirmed the following client releases for the upgrade:
- Execution: Besu 26.10.0, Ethrex 30.0.0-rc.2, Nethermind 2.2.0
- Consensus: Lodestar 1.50.0, Nimbus 26.10.1, Prysm v7.3.0, Teku 26.10.1
Ethrex's listed version is a release candidate. Operators should confirm that other client releases include support for this Hoodi activation.
What the scaling test changes
The 200 million gas target sets 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, rather than being instantly enforced.
Glamsterdam combines the Amsterdam upgrade on the execution layer with Gloas on the consensus layer. Key changes include enshrined proposer-builder separation, which 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 to allow clients to perform more work in parallel.
Developers should test contracts and gas estimation under the new rules, as changed gas pricing can affect contracts that rely on fixed stipends, hardcoded limits, or remaining-gas assumptions.
