Ethereum core developers have postponed activation of the Glamsterdam upgrade on the Hoodi testnet. The decision follows an analysis that identified eight smart contract invariants at risk of breaking under proposed changes to gas accounting.

The Ethereum Foundation confirmed the hold in a November 6 update. It stated that the Hoodi fork will remain suspended until the compatibility issues are resolved. No new activation date has been set.

ChainSecurity Findings Trigger Pause

Smart contract auditor ChainSecurity published an October 13 report examining the impact of EIP-8037 and EIP-8038. These proposals alter how the network charges gas for creating new state and accessing existing state. Many deployed contracts were written under the assumption that certain operations carry fixed or predictable gas costs.

The analysis showed that revised accounting can change behavior after external calls fail. Under current rules, a failed call may leave insufficient gas for subsequent instructions, causing the full transaction to revert. The new rules can restore access to previously unavailable gas, allowing contracts to continue and potentially record permanent failure states that developers never intended.

Other identified risks include contracts that assume gas consumption moves in only one direction, that fixed gas budgets remain sufficient, or that reverted calls cannot return gas already spent on state creation. Fixed gas budgets and gas reserves appear most frequently among the affected patterns.

Scope of the Review

Developers and independent auditors have been asked to examine both on-chain contracts and related off-chain systems such as wallets, relayers, and infrastructure that may contain hardcoded gas limits. Reports of affected contracts, the specific invariant involved, possible fixes, and supporting tests can be submitted for review before the next All Core Developers discussion.

The Foundation is collaborating with ChainSecurity and Dedaub while conducting its own internal audits. It has acknowledged that no single review can cover every project, especially those involving complex interactions between contracts and external systems. Depending on the feedback received, adjustments to the two EIPs may be considered before the upgrade advances.

Glamsterdam Progress Elsewhere

Glamsterdam already activated on the Sepolia testnet on October 6. That deployment included a gas limit increase to 200 million and allowed teams to begin examining the upgrade’s scaling features under realistic conditions. Key components include enshrined proposer-builder separation through EIP-7732, block-level access lists via EIP-7928, and the gas repricing changes now under scrutiny.

An earlier technical assessment based on historical transaction replays indicated that most contracts would remain unaffected. A smaller subset required higher gas limits or code modifications to avoid unexpected failures. Separately, developers resolved a validator deposit issue tied to the consensus-layer changes before incorporating regression tests into client implementations.

Work on the subsequent Hegota upgrade continues without interruption. The pause applies only to the Hoodi activation of Glamsterdam.

Next Steps for the Network

The All Core Developers group will evaluate the collected findings to decide whether specification changes are required or whether affected contracts can be updated independently. Until those questions are settled, the Hoodi hard fork stays on hold. Testing and development on other networks and subsequent roadmap items proceed in parallel.