Ethereum's Glamsterdam Upgrade Set for Sepolia Testnet on October 6

Ethereum developers have scheduled the network's next major protocol upgrade, Glamsterdam, to activate on the Sepolia testnet on October 6, 2026. Sepolia node operators must update both their execution-layer and consensus-layer clients ahead of the activation date, according to the Ethereum Foundation. Dates for rollout on the Hoodi testnet and mainnet have not yet been determined.

Glamsterdam introduces several significant protocol changes. Enshrined proposer-builder separation (ePBS) moves the handoff between specialized block builders and validators directly into Ethereum's protocol, reducing reliance on external middleware such as MEV-Boost. The upgrade also adds block-level access lists, which record the accounts and storage locations accessed during each block, and implements new gas pricing designed to more accurately reflect the cost of creating and reading on-chain data. Contracts depending on fixed gas stipends or hardcoded gas limits may require modifications to remain compatible.

Looking further ahead, developers are targeting 2027 for Hegotá, the upgrade expected to follow Glamsterdam. Ethereum co-founder Vitalik Buterin suggested on Sunday that Hegotá could be the network's last 'normal' fork before development pivots toward recursive STARKs, automated formal verification, optimized consensus mechanisms, and quantum-safe cryptography. Together, the Glamsterdam and Hegotá upgrades signal a strategic shift in Ethereum's long-term roadmap toward greater scalability and cryptographic resilience.