Glamsterdam Upgrade Scheduled for Sepolia in October
Ethereum's upcoming upgrade, Glamsterdam, is scheduled to activate on Sepolia at epoch 353,024, slot 11,296,768 (October 6, 2026, 13:53:36 UTC). This upgrade combines the Amsterdam execution layer and Gloas consensus layer upgrades. One of its key features is enshrined proposer-builder separation, which separates the roles of block proposers and builders in Ethereum's consensus protocol.
This change includes a builder's commitment to an execution payload, and the builder subsequently reveals that payload. The protocol handles payment to the proposer, reducing reliance on trusted middleware for the exchange between proposers and builders.
Glamsterdam also introduces block-level access lists (BALs), which record accounts and storage locations accessed during a block, together with post-transaction state changes. These lists allow clients to read state from disk in parallel, validate transactions in parallel, and compute state roots more efficiently.