ETH Upgrade Countdown Begins: 24 Hours Left for Glamsterdam Testnet Launch

The countdown is currently on for Ethereum's Glamsterdam upgrade, scheduled to activate on Sepolia at epoch 353,024, slot 11,296,768 on October 6, 2026, around 13:53:36 UTC.

Glamsterdam combines the Amsterdam execution layer upgrade with the Gloas consensus layer upgrade. Its headlining changes are enshrined proposer-builder separation (ePBS) and block-level access lists (BALs), which change how blocks are produced and validated to support greater L1 throughput.

The Sepolia testnet deployment brings Glamsterdam one step closer to its mainnet activation. Following a successful activation on Sepolia, Glamsterdam will launch on the Hoodi testnet, followed by the mainnet, on dates yet to be specified.

Ahead of the testnet launch on October 6, 2026 at 13:53:36 UTC, non-staking Sepolia node operators are urged to update their execution and consensus layer clients to releases that support the scheduled Sepolia activation.

This also applies to Sepolia stakers, who should ensure that both their beacon node and validator client are updated. They should also review their client's upgrade instructions for the new ePBS duties and any changes required to builder or validator tooling.

Glamsterdam improvements

EIP-7732 brings the separation between block proposers and builders into Ethereum's consensus protocol. The change also separates consensus validation from execution validation, giving validators more time to validate execution payloads.

EIP-7928 introduces enforced block-level access lists that record the accounts and storage locations accessed during a block, together with post-transaction state changes. Together, ePBS and BALs provide a foundation for scaling execution capacity while keeping block validation practical for node operators.

Glamsterdam adjusts gas accounting to better reflect resource usage. EIP-8037 increases and separately meters the cost of creating state, while EIP-8038 updates state-access costs.

The upgrade also includes ETH transfer logs, a slot-number opcode, a higher maximum contract size, a deterministic factory contract, and new stack-manipulation instructions. Consensus changes include forward-compatible data structures, excluding slashed validators from proposing, and increased exit and consolidation churn.