Ethereum's Glamsterdam Upgrade Scheduled for Sepolia Test Network

The Ethereum development team has announced that the Sepolia test network will undergo a major upgrade on September 28, 2026 at 14:44:48 UTC. The upgrade, codenamed Glamsterdam, was proposed in the minutes of an All Core Devs Call on August 20, 2026, and was accepted by six client teams without dissent.

The exact date and time for the upgrade were calculated based on the start of a new epoch and slot on the Sepolia test network. Epoch 351232, slot 11239424, corresponds to Monday, September 28, 2026 at 14:44:48 UTC.

While the date is provisional, as the decision was deferred to the next call, it marks an important milestone in the development of Ethereum's upcoming hard fork. The upgrade will be rolled out in stages, first on internal test networks, then on public test networks, and finally on the main network.