Ethereum has scheduled its Glamsterdam network upgrade for the Hoodi testnet on Oct. 26, 2026, following the upgrade’s activation on Sepolia on Oct. 6, according to the Ethereum blog post published Oct. 16, 2026. The announcement matters because Glamsterdam is described as part of Ethereum’s L1 scaling roadmap, with changes aimed at improving block production, validation and gas accounting. The mainnet activation date has not yet been decided.
Hoodi activation and gas limit increase
According to the announcement, Glamsterdam is set to activate on Hoodi at epoch 132,352, slot 4,235,264, which the post timestamps as Oct. 26, 2026 at 17:42:48 UTC. At the same epoch, Hoodi’s gas limit will be raised to 200M, matching Sepolia. The post also says node operators must update both execution and consensus layer clients before activation.
The announcement includes a deployment table showing Sepolia already activated on Oct. 6, while mainnet remains listed as TBD. It says Hoodi-compatible client versions will be added to the release tables as they are confirmed, and that only releases whose notes explicitly confirm support for the Hoodi Glamsterdam activation should be used.
What Glamsterdam changes
Glamsterdam combines the Amsterdam execution layer upgrade with the Gloas consensus layer upgrade, and its headlining changes are enshrined proposer-builder separation, or ePBS, and block-level access lists, or BALs. The post says these changes are intended to support greater L1 throughput while keeping block validation practical for node operators.
Under EIP-7732, ePBS brings the separation between block proposers and builders into Ethereum’s consensus protocol. The post says a proposer includes a builder’s commitment to an execution payload, with the builder later revealing that payload. It adds that the protocol handles payment to the proposer, reducing reliance on trusted middleware for proposer-builder exchange, and separates consensus validation from execution validation so validators have more time to validate execution payloads.
EIP-7928 introduces enforced block-level access lists that record the accounts and storage locations accessed during a block, along with post-transaction state changes. Ethereum says those lists allow clients to read state from disk in parallel, validate transactions in parallel and compute state roots more efficiently.
Gas pricing, contracts and developer impact
The upgrade also changes gas accounting. Ethereum says EIP-8037 increases and separately meters the cost of creating state, while EIP-8038 updates state-access costs. Additional changes cover intrinsic transaction gas, calldata, access lists and block gas accounting. The post advises application developers to test contracts and gas estimation against the new rules, warning that contracts relying on fixed gas stipends, hardcoded gas limits or assumptions about remaining gas may need changes.
Beyond the core scaling changes, Glamsterdam includes ETH transfer logs, a slot-number opcode, a higher maximum contract size, a deterministic factory contract and new stack-manipulation instructions. Consensus changes also include forward-compatible data structures, excluding slashed validators from proposing, and increased exit and consolidation churn.
Client releases and operator guidance
The announcement lists Hoodi-compatible client releases across the consensus, execution and tooling stacks, including Grandine, Lighthouse, Lodestar 1.50.0, Nimbus 26.10.1, Prysm Teku 26.10.1, Besu 26.10.0, Ethrex 30.0.0-rc.2, Nethermind 2.2.0, Reth and commit-boost 0.12.0-rc1. It says validator operators running a beacon node and validator client must update both components before activation, and that operators using external block-building infrastructure should review Glamsterdam-specific upgrade instructions.
The post says Ethereum’s Bug Bounty Program is active for Glamsterdam specifications and EIPs, with client implementations becoming eligible as soon as their releases are added to the client release tables. For mainnet users and ETH holders, the announcement says no action is required. The mainnet activation timing remains unknown and will be announced separately.
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