Ethereum Glamsterdam Upgrade Targets Oct 6 Sepolia Fork
Ethereum developers have reached an agreement to activate the Glamsterdam upgrade on the Sepolia testnet on October 6 at 13:53 UTC. This milestone marks a significant step towards implementing the network's next major upgrade, but it is still tentative and depends on successful devnet transition.
The Glamsterdam upgrade aims to increase Ethereum's L1 capacity by introducing Block-Level Access Lists (BALs) and proposer-builder separation (PBS). BALs identify which parts of the state a block accesses and modifies, allowing clients to understand dependencies before executing transactions. PBS, on the other hand, brings the relationship between validators and block builders directly into consensus.
The testing sequence is crucial in ensuring the stability of Glamsterdam. Developers will first test it on devnets, followed by Sepolia and Hoodi, before committing to mainnet activation. The official roadmap targets Glamsterdam for mainnet during the fourth quarter of 2026, but a specific date has not been announced.