Ethereum's Glamsterdam upgrade due on Hoodi testnet Oct. 26

At 17:42:48 UTC on October 26, 2026, the Hoodi test network is scheduled to switch to Glamsterdam, the next major upgrade of Ethereum's base layer. The switch is fixed in advance at epoch 132,352 and slot 4,235,264, which are checkpoints in the chain's own clock. Hoodi is a test network, so the change does not touch money or accounts on the main chain. It is the second rehearsal, after Sepolia, which made the same switch on October 6.

Glamsterdam is two upgrades bundled together: the Amsterdam upgrade to the execution layer, which runs transactions, and the Gloas upgrade to the consensus layer, which agrees on the order of blocks. Its two headline changes concern how blocks are built and checked. With enshrined proposer-builder separation (ePBS), a proposer commits to a builder's payload, the builder reveals it later, and the protocol itself handles the payment to the proposer, reducing reliance on trusted middleware. Block-level access lists (BALs) record the accounts and storage locations a block touches, so that clients can read state and validate transactions in parallel rather than one after another.

The upgrade also changes gas pricing, the fee units that measure the work a transaction demands. The Ethereum Foundation says the new costs better reflect the price of execution and of state growth, the data the network must keep. Creating new state becomes more expensive and is metered separately, and state-access costs are updated. Contracts that rely on fixed gas stipends, hardcoded gas limits or assumptions about remaining gas may need changes, which is why developers are pointed to a repricing impact guide.

What changes concretely, and for whom? For node operators, the answer is a deadline: both execution and consensus software must be updated before October 26, and validators must update both the beacon node and the validator client. For developers, it means re-testing contracts and gas estimates against the new rules now. For everyone else, nothing changes on the main network yet, because no mainnet date has been decided. Client teams will announce one when it is fixed.