Ethereum's next major network upgrade, Glamsterdam, is scheduled to launch on the Sepolia testnet on October 6, with activation set for 16:53 Turkish time (13:53 UTC).

Sepolia is one of Ethereum's public testnets — live networks where upcoming protocol changes are rehearsed under real conditions before reaching the mainnet. According to the schedule announced by the Ethereum Foundation, the upgrade will be activated at epoch 353,024 and slot 11,296,768. Validators running on Sepolia need to upgrade both their execution and consensus layer software to the specified versions before activation, giving client teams and node operators a shared environment to verify the changes in practice.

Glamsterdam combines two upgrades into a single package: the Amsterdam update at the execution layer and the Gloas update at the consensus layer.

A New System for Block Production

One of the most important features of the update is the separation, at the protocol level, between validators — which propose blocks — and the structures that prepare them. The system, known as ePBS, aims to make the block production process more reliable and efficient. Until now, this division of labor has largely taken place outside the protocol through off-protocol infrastructure such as MEV-boost, and ePBS would move that coordination into Ethereum's core rules.

The update also introduces block-level access lists, which are designed to indicate in advance which Ethereum data transactions will touch. It is stated that this structure could help with parallel transaction processing and increasing Ethereum's mainlayer capacity in the future.

Scope and Next Steps

The October 6 activation applies only to the Sepolia testnet, a step consistent with how Ethereum has rolled out recent major upgrades such as Dencun and Pectra through public testnets before mainnet activation. $ETH holders do not need to take any action, and no exact date has been confirmed for when the upgrade will go live on the Ethereum mainnet. The mainnet schedule will be determined once test results are available, keeping attention on how the upgrade performs on Sepolia.

*This is not investment advice.