Ethereum Glamsterdam Upgrade Targets Oct. 6 for Sepolia Test

Ethereum developers have tentatively scheduled the Glamsterdam network upgrade for activation on the Sepolia testnet on October 6, 2026, at 1353 UTC. The date, agreed upon during the September 3 All Core Developers Consensus meeting, is conditional on the successful outcome of a critical private test network that has not yet launched. The upgrade's timeline has already slipped multiple times. Glamsterdam was originally targeted for the first half of 2026, then pushed to the fourth quarter in August. The Sepolia activation was first scheduled for August 3 before being moved to October 6. The primary obstacle is the need for a stable run on a private development network. The latest test, Devnet9, launched on September 1 with 1,000 validators and is still unable to finalize blocks normally. Finality is the process by which validators agree on the blockchain's state, ensuring transactions are permanent. Its absence on a test network indicates weaker security and unresolved technical issues. Developers have now skipped the planned Devnet10 and moved directly to Devnet11, which is scheduled to launch on September 14 with 84,000 validators.