Ethereum developers have postponed the Glamsterdam upgrade on Hoodi, the public testnet used for final rehearsals of network upgrades, where activation had been scheduled for October 26, 2026. No new date has been announced.

The decision was made during All Core Devs Execution call #248. All Core Devs calls are where Ethereum's client teams coordinate protocol changes. The Ethereum Foundation, which announced the delay in a blog post published on October 22, said the pause gives developers time to study how some of the proposed changes interact with smart contracts already deployed on Ethereum, rather than proceed on the original schedule.

What the Delay Covers

Three planned changes have been removed from the October 26 date: the Amsterdam execution layer activation, the Gloas consensus layer activation, and a plan to raise Hoodi's gas limit to 200 million. None of the three changes will activate on Hoodi until a revised schedule is confirmed.

The postponement does not unwind Hoodi's chain history, and mainnet users and ETH holders do not need to take any action. Node and validator operators, however, must update their software. Clients such as Lodestar, Besu, and Nethermind must run versions that confirm the October 26 activation has been removed.

Glamsterdam already went live on the Sepolia testnet on October 6, and that network is not affected by the delay. Ethereum stages its upgrades across several public testnets before mainnet activation, so a clean Sepolia launch does not by itself clear the upgrade for mainnet.

Security Firm Raises Gas Concerns

The postponement follows an October 13 warning from blockchain security firm ChainSecurity, which flagged two Glamsterdam proposals, EIP-8037 and EIP-8038, covering gas repricing within the upgrade. Repricing proposals adjust the gas cost assigned to specific operations. According to the firm, the changes could weaken protections against an attack known as insufficient gas griefing, in which a caller supplies a smart contract with too little gas to finish a valid task. Gas is the measure of computational work required to execute operations on Ethereum.

ChainSecurity said the new rules could allow gas to return to a contract after an operation fails, meaning execution would keep running in cases where it would previously have stopped. That could create problems for contracts that rely on gas checks for security. A contract could, for example, remove a user's claim or block a retry, leaving the user unable to complete a valid action. Smart contracts run under whatever rules the chain enforces at execution time, which is why protocol-level gas changes can reach deployed code their authors never update.

The firm cautioned that not all gas-based safety checks would fail. Some would continue to work, but developers would need to review them against the new rules.

On October 21, security researcher pcaversaccio called the risks "serious" in a GitHub comment and asked developers to reassess the hard fork. The Ethereum Foundation had earlier warned that Glamsterdam's gas model could break some wallets, indexers, and gas estimators that rely on fixed assumptions.

On Friday, ChainSecurity said it had found 13 real-world smart contracts that could be affected. The firm did not name the projects and said it is working with them on responsible disclosure, the practice of reporting vulnerabilities privately so affected teams can address them before details are made public. It also urged developers to check their contracts as soon as possible.

What Comes Next

Glamsterdam is Ethereum's main scaling upgrade for 2026. It includes enshrined proposer-builder separation under EIP-7732, block-level access lists under EIP-7928, and gas repricing under EIP-8037 and EIP-8038. "Enshrined" refers to features written directly into the protocol itself rather than provided by software outside the consensus rules.

Developers had been looking at early December for a mainnet launch, depending on successful Hoodi testing. That fourth-quarter window remains open, with a revised Hoodi date expected after Devcon, Ethereum's flagship developer conference, which runs November 3 to 6. After the conference, watch for the revised Hoodi activation date, the outcome of ChainSecurity's coordination with the 13 affected projects, and client releases confirming that the October 26 activation has been removed.

ETH's price showed little reaction to the postponement, since the issue affects only the testnet. Institutional buying has continued, with SharpLink deploying $400 million of its ETH treasury on-chain and BitMine adding 12,535 ETH to its holdings.

Source: Blockonomi