Glamsterdam Sepolia Testnet Upgrade

Ethereum (ETH) · Releases & Updates · October 6, 2026

Ethereum's Glamsterdam hard fork activates on the Sepolia testnet on October 6, 2026 at 13:53 UTC, the first public testnet step before mainnet.

Glamsterdam, Ethereum's next hard fork (ePBS, Block-Level Access Lists, gas repricing), reaches its first public testnet: the Sepolia upgrade is scheduled for October 6, 2026 at 13:53 UTC, and Sepolia node operators must upgrade clients by October 5. Sepolia will signal a 200M gas limit at the fork, rising gradually from 60M. Next steps per the Ethereum Foundation Protocol cluster: ACD go/no-go on Hoodi on October 8, a tentative Hoodi upgrade around October 27, and a potential Ethereum mainnet window no earlier than early December after a roughly 30-day security period. Mainnet is not yet scheduled.

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Last verified: October 27, 2026 · Source: x.com

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