Ethereum's Glamsterdam Upgrade Hit Another Testing Hurdle

Ethereum developers have tentatively scheduled the Glamsterdam upgrade for activation on the Sepolia testnet on October 6 at 13:53 UTC, according to minutes from the Ethereum ACDC #186 meeting shared by reporter Christine D. Kim. The date, however, is far from confirmed.

Devnet Instability Clouds the Timeline

The decision to target October 6 comes after a difficult stretch of internal testing. A stable Glamsterdam devnet has not yet emerged. Devnet-9, which runs 1,000 validator nodes, is still unable to complete finalization normally. Before that, a major consensus-layer vulnerability was discovered on Devnet-8 that could have caused the entire network to halt. Separately, issues were found in the execution layer tied to EIP-8037, requiring implementation updates from every client team.

Developers are now preparing Devnet-10 to address these problems before any public testnet deployment proceeds. If Devnet-10 also proves unstable, the October 6 Sepolia activation will likely be pushed back again. Upgrade dates for the Hoodi testnet and Ethereum mainnet remain undetermined.

What Is at Stake With Glamsterdam

Glamsterdam is widely regarded as Ethereum's most significant protocol change since the Merge. The upgrade ships ten Ethereum Improvement Proposals under the Glamsterdam Meta EIP-7773, with two headline changes doing the structural heavy lifting: EIP-7732, which enshrines Proposer-Builder Separation (ePBS) directly into the protocol, and EIP-7928, which introduces Block-Level Access Lists (BALs) to enable parallel execution.

EIP-8037, the proposal at the center of the current testing problems, introduces a separate gas dimension for state-creating operations such as new account creation, contract deployment, and new storage slots. The Ethereum Foundation's Protocol DevOps team has warned any tool relying on a hardcoded maximum gas limit "will break," naming wallets, indexers, and gas estimators among affected software. Developers have been urged to test on the Plataberget testnet in the meantime.

The delays are not entirely surprising given the upgrade's scope. Glamsterdam was originally targeted for the first half of 2026 before being pushed back as the complexity of shipping ePBS and BALs together became clearer. Past Ethereum hard forks have typically required several months of public testnet seasoning before a mainnet date is set, putting any realistic mainnet window deep into late 2026 at the earliest.

Sources:
PANews: Ethereum Developers Tentatively Plan Glamsterdam Activation on Sepolia for October 6
Everstake: Ethereum Glamsterdam Upgrade Explained
Crypto.news: Ethereum Devs Warn Glamsterdam Could Break Wallets and Gas Tools