Ethereum will activate the Glamsterdam upgrade on the Sepolia testnet on October 6 at 13:53:36 UTC, introducing changes designed to increase the network's execution capacity. The upgrade brings a scheduled 200 million gas preference that could expand block capacity and ease congestion during periods of high demand.
Node operators and validators must update their execution, consensus, and validator software before the fork. However, simply upgrading software will not automatically move the network toward the 200 million gas target. Prysm 7.2.0 and Teku 26.9.1, two major consensus clients, will continue defaulting to a 60 million gas preference after activation unless validators explicitly change their configuration settings.
A higher block gas limit allows more computation to fit into each block, creating room for additional transactions and complex applications such as decentralized exchanges. This expanded capacity can reduce congestion and ease pressure on transaction fees during high-demand periods, though it does not affect Ethereum's underlying block times.
Ethereum has already been incrementally raising its gas limit. The block gas limit began rising from 30 million toward 36 million in February 2025, the first adjustment since the network transitioned to proof-of-stake. It subsequently climbed to 45 million before reaching 60 million as a client default.
Glamsterdam combines the Amsterdam execution upgrade with Gloas on the consensus layer and introduces enshrined proposer-builder separation alongside block-level access lists. These access lists allow clients to parallelize state reads and transaction validation, laying groundwork for higher Layer 1 throughput.
The upgrade includes safeguards as capacity increases. A 16.7 million gas cap limits how much of a block any single transaction can consume, meaning higher block limits primarily create room for aggregate activity rather than allowing individual operations to expand without restraint.
According to Ethereum Foundation guidance, Prysm operators must use version 2 proposer settings or the keymanager API to change their preferences, while Teku validators can override defaults through their validator configuration. The Sepolia test will provide the first scheduled trial of Glamsterdam before developers decide on activation for other networks. Hoodi and mainnet activation dates remain undecided.
