The Ethereum Foundation announced that the Glamsterdam upgrade will activate on the Hoodi testnet on Oct. 26, 2026. The upgrade is expected to increase throughput on Ethereum’s base layer, optimize block validation and change gas-fee accounting mechanisms.

Glamsterdam will activate at epoch 132,352 and slot 4,235,264. At the same time, Hoodi’s gas limit will increase to 200 million, matching the increase made on the Sepolia testnet when the upgrade activated there on Oct. 6.

Changes planned for Ethereum

Glamsterdam combines changes from the Amsterdam execution layer and the Gloas consensus layer. Its main components include protocol-level separation of block building and proposing, known as ePBS, and block-level data access lists, or BALs.

The ePBS mechanism proposed in EIP-7732 separates validators that propose blocks from participants that build them. The protocol will coordinate interactions and payments between those parties, reducing reliance on trusted intermediaries and giving validators more time to verify transaction execution.

BALs, described in EIP-7928, will record the accounts and storage accessed while a block is processed, along with state changes after transactions. This is intended to help clients read data in parallel, verify transactions and compute state roots more efficiently.

The upgrade will also change gas calculations to account more accurately for resource use and growth in blockchain state. EIP-8037 increases and separately accounts for the cost of creating state, while EIP-8038 updates state-access costs.

Other planned changes include Ethereum transfer logs, a new opcode for retrieving the slot number, an increase in the maximum smart-contract size and revised operating rules for validators.

Testing and operator requirements

During earlier Glamsterdam testing on Sepolia, developers identified a vulnerability in the block-auction system. The issue allows attackers to outbid legitimate bids and then fail to propagate transactions after winning.

Hoodi node operators and validators must update their execution- and consensus-layer clients to compatible versions before activation. Validators also need to review requirements for the new block-production process and confirm that their tools are compatible.

Application developers are advised to test smart contracts on the updated Sepolia and Hoodi networks and assess whether the new gas-accounting rules affect their projects. Contracts that depend on fixed gas limits or assumptions about remaining gas may require changes.

The Ethereum Foundation will announce the mainnet activation separately. Mainnet users and asset holders do not need to take any action in connection with the Hoodi launch at this time.

The Ethereum team previously launched the Platåberget testnet in August to test the Glamsterdam upgrade.

Source: Incrypted