Ethereum is preparing to activate the Glamsterdam upgrade on the Sepolia testnet on October 6, moving one of its largest upcoming Layer 1 redesigns onto a long-lived public testing environment. According to the Ethereum Foundation’s official Glamsterdam testnet announcement, activation is scheduled for epoch 353,024, slot 11,296,768, at 13:53:36 UTC. The Sepolia fork is a testnet deployment, not an Ethereum mainnet upgrade, and neither Hoodi nor mainnet currently has a scheduled activation date.
Glamsterdam combines Amsterdam on Ethereum’s execution layer with Gloas on its consensus layer. Its headline changes are Enshrined Proposer-Builder Separation under EIP-7732 and Block-Level Access Lists under EIP-7928, alongside extensive changes to gas accounting and state management. The Sepolia deployment follows earlier experimentation on the Platåberget public testnet, which was created specifically to expose Glamsterdam changes to developers and infrastructure providers before they reached Ethereum’s established testnets. Sepolia therefore represents another stage of validation rather than Glamsterdam’s first public test deployment.
ePBS and BALs Reshape Block Processing
EIP-7732 moves key parts of the proposer-builder relationship directly into Ethereum consensus. Builders commit to an execution payload and payment before subsequently revealing the payload, while a Payload Timeliness Committee determines whether the data arrived on time. By enforcing more of the proposer-builder exchange at the protocol level, ePBS reduces reliance on trusted middleware for payment and payload delivery without necessarily eliminating every external block-building service.
The mechanism also separates consensus validation from execution validation, giving validators additional time to process execution payloads. That architectural change is intended to make higher execution capacity more practical. Ethereum client development has been preparing for these new responsibilities for months, including Prysm releases carrying Gloas and ePBS-related infrastructure. Sepolia will provide a broader environment for determining whether those client implementations interoperate correctly under the new block-production model.
EIP-7928 approaches scaling from the execution side. Block-Level Access Lists record which accounts and storage locations a block touches, together with relevant state changes, allowing clients to fetch state and validate transactions more concurrently. BALs create infrastructure for greater parallelism, but they do not mean every Ethereum transaction suddenly executes in parallel after the October 6 fork.
Glamsterdam also substantially changes gas accounting. EIP-8037 increases and separately meters state-creation costs, while EIP-8038 reprices state access, with additional changes affecting calldata, intrinsic gas and block accounting. Those changes form part of Ethereum’s wider effort to raise Layer 1 capacity while controlling the resource costs of larger blocks. Contracts and tooling that depend on hardcoded gas limits or fixed gas assumptions may therefore require adjustments even when their core application logic remains unchanged.
Sepolia Operators Must Upgrade Before Activation
The Ethereum Foundation has published Sepolia-compatible versions across major execution and consensus clients. Node operators need to update both layers before the fork, while validators must also ensure their beacon node and validator client support Glamsterdam. Software that does not understand the new consensus rules will be unable to follow the upgraded Sepolia chain after activation.
The transition also introduces configuration details for validators. Prysm and Teku, for example, support the Sepolia fork but default to a 60 million gas limit after activation unless operators explicitly configure a 200 million limit. External builder infrastructure must separately support the new ePBS duties and interfaces. Client compatibility therefore involves more than installing a release number; operators also need to review configuration and builder-tooling requirements.
No action is required from ordinary Ethereum mainnet users or ETH holders. Hoodi activation parameters remain undecided, and the Foundation says a separate announcement will cover mainnet once client teams determine the schedule. A successful Sepolia fork would demonstrate that Glamsterdam can operate on a persistent public testnet, but it would not constitute approval or scheduling of the upgrade for Ethereum mainnet.
Jack Reynolds is SatoshiPick’s infrastructure mind. Based in Denmark, he follows Bitcoin, Ethereum, Layer 1 networks, stablecoins and DeFi with a practical question always in the background: does this actually make crypto work better?
His articles focus on the systems beneath the headlines: settlement rails, protocol upgrades, stablecoin usage, DeFi coordination and the regulatory limits around them. Jack avoids turning technical coverage into a maze. He explains what is live, what is still experimental and why the difference matters.