Ethereum developers decided to delay the Glamsterdam upgrade on the Hoodi testnet, originally scheduled for October 26, 2026. The decision, announced by the Ethereum Foundation on Thursday (22), came after concerns about how new gas charging rules could change the behavior of existing smart contracts.
The delay was decided during the ACDE #248 meeting to allow a deeper investigation of the EIP-8037 proposal and its interaction with contracts used on mainnet. There is still no new activation date.
The change also suspends the scheduled increase in Hoodi's gas limit to 200 million units per block, which was scheduled to occur alongside Glamsterdam. The execution and consensus layer activations were removed from the upgrade configuration.
The problem involves a compatibility issue: certain contracts may react differently to unsuccessful operations, even without changes to their code.
How the new gas rules can affect existing contracts
Gas represents the computational cost of operations executed on Ethereum. Two proposals included in Glamsterdam modify this accounting: EIP-8037 separates the costs of creating new records on the blockchain, while EIP-8038 changes the amounts charged for accessing and modifying data.
In a technical analysis published on October 13, security firm ChainSecurity demonstrated that these changes can interfere with the mechanisms used by smart contracts to handle failures.
Some contracts allow an external operation to fail without immediately interrupting all processing. To avoid problems, they check how much gas remains available before recording the error or preventing further attempts.
With the proposed rules, however, an unsuccessful operation may return or preserve enough gas for error handling to be completed. A failure that previously would have caused the transaction to revert could come to be recorded permanently, depending on the contract's logic.
The investigation also identified the opposite problem: operations that were previously executable may come to consume more gas than the budget anticipated by the developer.
In an example presented by ChainSecurity, the creation of a new storage record goes from 22,100 to 110,020 units of gas. Of that total, 97,920 correspond to state creation and 12,100 to execution. When the separate gas reserve for state creation is exhausted, the entire cost must be covered by execution gas.
These results demonstrate compatibility risks under specific conditions, not a widespread vulnerability. The analysis does not prove that contracts are being exploited on mainnet because of these changes.
For Hoodi node operators and validators, the Ethereum Foundation advises reviewing the execution and consensus layer software before October 26. Configurations that still retain the original activation must be updated according to the instructions from the respective developers.
The delay does not reverse previous transactions, nor does it undo the Glamsterdam activation carried out on the Sepolia testnet on October 6. The mainnet upgrade still has no officially defined date, and ordinary users or ETH holders do not need to take any action.
