Ethereum Sets Glamsterdam on Hoodi for 26 October

What changed

On 16 October 2026 the Ethereum Foundation Protocol Cluster scheduled the Glamsterdam upgrade for the Hoodi testnet. Activation is epoch 132352, slot 4235264, at 17:42:48 UTC on 26 October 2026. At that same epoch Hoodi's gas limit rises to 200 million, matching Sepolia. Sepolia activated Glamsterdam on 6 October 2026 at 13:53:36 UTC, epoch 353024, slot 11296768. Mainnet is still blank. The foundation said the mainnet time will be announced once client teams decide it, and that Hoodi compatible client releases will be added to the client tables as they are confirmed. Node operators have to update both the execution client and the consensus client before Hoodi activates.

Glamsterdam pairs the Amsterdam execution layer fork with the Gloas consensus layer fork. The two headline changes are enshrined proposer builder separation, EIP 7732, and block level access lists, EIP 7928. Under EIP 7732 a proposer includes a builder's commitment to an execution payload, and the builder reveals that payload later. The protocol pays the proposer, which is meant to reduce reliance on trusted middleware. Consensus validation is split from execution validation, so validators get more time to check the payload. A payload timeliness committee attests that the builder revealed the payload, and that the blob data was available, on time.

EIP 7928 forces each block to carry the accounts and storage locations it touched, plus the post transaction state changes. Clients can then read state in parallel, validate transactions in parallel, and compute state roots with less serial work.

Gas accounting changes with the fork. EIP 8037 raises and separately meters the cost of creating state. EIP 8038 updates the cost of accessing state. The announcement also points to changes in intrinsic transaction gas, calldata, access lists, and block gas accounting. The scheduled work also includes ETH transfer logs, a slot number opcode, a higher maximum contract size, a deterministic factory, new stack instructions, forward compatible consensus data structures, excluding slashed validators from proposing, and higher exit and consolidation churn. The bug bounty already covers the specifications. Client code becomes eligible when a release is listed in the client tables.

The cover is a photograph from Ethereum Devcon in Prague. It is an attendee shirt, not a picture of the Hoodi testnet.

Why it matters

Hoodi is the staking and infrastructure testnet. A 200 million gas limit, plus a new split between who proposes a block and who builds it, is the first public rehearsal of Ethereum's next layer one scaling plan outside Sepolia. Application developers who hardcode gas, or who assume a call still has the same leftover gas as it did last year, can break on Hoodi even when the contract logic is unchanged. Validator and builder teams have new duties. Missing the client upgrade means a node that does not follow the fork.

This is not a mainnet date. Treating 26 October as a production migration would be a misread of the announcement.

Who is affected

Hoodi validators, staking operators, relays, and builder teams have a deadline. Teams that deploy on Sepolia can already test. Everyone else should use the ten days before Hoodi to see whether gas estimation and contract size limits still match their deployments. The photographs are from earlier Ethereum community events. They are not Hoodi, and they are not client release images.

Photo: Wikimedia Commons. Devin Finzer at Devcon 5 in Osaka, on tradeable tokens. An Ethereum community event, not the Hoodi testnet.

Photo: TechCrunch, via Wikimedia Commons. Vitalik Buterin at TechCrunch Disrupt London on 8 December 2015. Not a photograph of the 2026 Hoodi upgrade.

What to do next

Update Hoodi execution and consensus clients when the release table names them. Do not wait for a mainnet blog post to test gas. Run the foundation's repricing impact guide against contracts that use fixed stipends or hardcoded gas limits. Builder operators should read the payload timeliness duties before epoch 132352.

What to watch

The client release table, the still empty mainnet row, and any bug bounty report that touches the Hoodi configuration. Also watch whether Hoodi actually holds the 200 million gas limit after activation, or whether operators vote it down.

Sources

• Primary — Ethereum Foundation Protocol Cluster, Glamsterdam Hoodi Testnet Announcement (16 October 2026). Establishes the Hoodi epoch, slot, timestamp, 200 million gas limit, the Sepolia activation, the open mainnet date, and the EIP list.