Ethereum’s Glamsterdam upgrade targets major protocol overhaul, with mainnet timing still unsettled

Ethereum core developers are preparing the Glamsterdam upgrade, a protocol overhaul described in the source article as the biggest since The Merge. The package combines the execution-layer "Amsterdam" track and the consensus-layer "Gloas" track, and is aimed at advancing L1 scaling by changing how Ethereum processes transactions, validates blocks, and manages its growing database. The work centers on three goals: safer parallel transaction processing, higher throughput through a clearer split between block building and validation, and a more sustainable fee model that better reflects long-term hardware costs tied to data growth. Two headline proposals sit at the center of the plan: enshrined proposer-builder separation, or ePBS, on the consensus side, and block access lists, or BALs, on the execution side. The package also includes repricing proposals for storage-heavy actions and for read operations on existing chain data. A mainnet launch date has not been finalized. A widely cited schedule had pointed to a Sept. 16, 2026 activation after Devnet iterations and Sepolia and Hoodi testnet forks, but the article says the timeline has likely slipped again. EthPandaOps has introduced a short-lived public testnet called Plataberget, while Sepolia and Hoodi deployments are now expected in September, pushing the mainnet target into the fourth quarter of 2026.