Ethereum Glamsterdam Upgrade Moves to Public Testnet Following Devnet Success
Ethereum has cleared a private devnet rehearsal for its upcoming Glamsterdam upgrade, with a public testnet deployment on Sepolia set for October 6, 2026.
The Ethereum network is moving forward with the Glamsterdam upgrade after successfully completing a private devnet rehearsal. Developers have scheduled a public testnet deployment on the Sepolia network for October 6, 2026, at 13:53 UTC. If testing remains stable, the upgrade is expected to reach mainnet in Q4 2026.
Glamsterdam represents a significant capacity expansion for the network, with plans to increase the block gas limit from approximately 60 million to 200 million. The upgrade combines consensus-layer changes known as Gloas with execution-layer updates called Amsterdam.
A primary feature of the upgrade is the implementation of enshrined proposer-builder separation, or ePBS, via EIP-7732. This change aims to move block production away from off-protocol MEV relays, which currently introduce centralization risks, and instead bake the separation directly into the Ethereum protocol.
Additionally, EIP-7928 introduces block-level access lists, or BALs. This allows transactions to declare which parts of the network state they will interact with, facilitating safer parallel execution. These technical adjustments are projected to lower transaction fees for many common operations by an estimated 78.6%.
The path to the Sepolia testnet follows earlier testing on Devnet-11 and the Platåberget environment. Previous devnet cycles identified implementation bugs and finality issues, leading developers to prioritize stability over speed. This cautious testing process is consistent with the approach taken during the Pectra and Fusaka upgrades.
As part of the Surge phase of Ethereum’s roadmap, Glamsterdam focuses on scaling the base layer. By increasing L1 capacity, the upgrade is expected to allow Layer 2 rollups like Arbitrum, Optimism, and Base to post data more efficiently, ultimately improving throughput across the ecosystem.
While the October 6 date is currently tentative, a successful testnet run would shift focus toward finalizing a mainnet activation date for later in 2026.
