The postponement of the Glamsterdam upgrade was agreed upon during the October 22, 2026, All Core Developers Execution meeting #248.

From the articleEthereum's long-awaited Glamsterdam upgrade hits another roadblock as 13 security risks emergeAlso in Ethereum Glamsterdam Delay: ChainSecurity Flags 13 Contracts Where Failures Turn Permanent, Ethereum Delays Oct 26 Glamsterdam Hoodi Upgrade Over Security Risks, Ethereum delays Glamsterdam test after security devs flag risk to existing contracts, Ethereum Delays Glamsterdam Testing After 13 Contracts Trigger Concerns, Ethereum postpones Glamsterdam upgrade on Hoodi testnet over smart contract concerns