Glamsterdam activates on the Sepolia test network with a block capacity of 200 million gas, more than three times today's limit. Success would clear the way to schedule the next test network.
Ethereum's next major upgrade, Glamsterdam, goes live on the Sepolia public test network on Tuesday, marking the first public rehearsal of a more than threefold jump in block capacity.
The upgrade is scheduled to activate at 13:53:36 UTC, 9:53 a.m. Eastern, at epoch 353,024. Developers have said dates for the next test network, Hoodi, and for Ethereum's main network have not been set.
What changes
Glamsterdam bundles three main features. Enshrined proposer-builder separation, known as ePBS, moves the division of labor between those who propose blocks and those who build them into the core protocol rather than relying on outside software. Block-level access lists let nodes know in advance which parts of the network's state a block will touch, enabling more parallel processing. And a repricing of gas costs aligns fees more closely with the computing work transactions require.
The headline test is capacity. Sepolia will run with a 200 million gas limit per block, compared with the 60 million gas that applies otherwise, a more than threefold increase.
The last-minute patch
Getting there required a late fix. Prysm, one of the most widely used consensus clients, released version 7.2.1 late Monday so validators would automatically adopt the 200 million gas setting when the upgrade activates. Operators running the older version would have stayed at 60 million unless they changed it manually, which could have split the test network's capacity between upgraded and non-upgraded validators.
The patch underscores a tension in Ethereum's process. Coordinating dozens of independent client teams is what makes the network resilient, but it also means small configuration gaps can surface hours before a scheduled fork.
Why it matters for ether
Scaling the base layer has been central to the case for ether, which outperformed bitcoin in the third quarter. A clean Sepolia run would keep the upgrade on track for later testing and give developers evidence that the network can handle much larger blocks without stalling.
Ether traded at $2,716.35 early Tuesday, up 0.24%. Testnet results rarely move the price directly, but a failed or delayed test would push back the mainnet timeline that investors are counting on.
The signals to watch are finality and participation. If Sepolia blocks finalize normally at the higher limit and validator participation stays high, developers will be in a position to set a Hoodi date. Any stall or missed finality would send the client teams back to the drawing board.