Ethereum’s Glamsterdam upgrade activated on the Sepolia test network on October 6, FinanceFeeds reported, describing continued block production and finalisation after the fork. Its early observation is evidence of an initial transition, not a comprehensive assessment of client health or long-term performance. Source
The timing matches the Ethereum Foundation’s schedule: 13:53:36 UTC, beginning at epoch 353,024 and slot 11,296,768. The cross-client Sepolia configuration records the same activation parameters. Hoodi and mainnet dates remain unassigned in the Foundation’s announcement. Schedule | Configuration
What the test changes
Glamsterdam pairs Amsterdam, the execution-layer upgrade, with Gloas on the consensus layer. The engineering task is to change how Ethereum builds and checks blocks while keeping validation manageable for operators.
One central component is enshrined proposer-builder separation, or ePBS. Under EIP-7732, a block proposer can include a builder’s signed commitment rather than the complete execution payload. The builder subsequently reveals that payload, while the protocol handles the associated payment to the proposer.
This changes the division of work. Consensus checks and execution checks occur separately, allowing more time for execution validation. Selected validators also attest to whether the promised payload and related data arrived on time. It brings responsibilities that previously depended on middleware into the protocol and creates new duties for validator and builder infrastructure.
Giving clients a map of the block
The second major change concerns the information a client receives before validating transactions. EIP-7928 introduces block-level access lists that record accessed accounts, storage locations and resulting state changes.
That information makes dependencies visible. Clients can organise disk reads and transaction validation in parallel and calculate the resulting state more efficiently. The intended benefit is additional processing capacity without requiring every check to wait for the previous operation.
Those are design capabilities. An initial testnet transition does not establish a measured throughput improvement under sustained use, and it cannot establish what future mainnet transaction fees will be.
Gas assumptions need another look
Application developers have a separate task. EIP-8037 raises and separately measures the cost of adding new state, while EIP-8038 revises charges for state access. These changes address resource use and database growth as Ethereum explores higher capacity.
The Foundation advises developers to test contracts and gas estimation against the new rules, particularly where code relies on fixed gas stipends, hardcoded limits or assumptions about remaining gas. A familiar application interface can conceal an execution assumption that needs adjustment.
What ETH holders should expect next
Sepolia operators needed compatible execution and consensus clients, including updated validator software where applicable. Ordinary mainnet users and ETH holders need take no action because of this testnet event, the Foundation says.
A separate announcement will set out any mainnet activation. Until then, the useful questions concern testnet stability, application compatibility and operator readiness. A testnet milestone alone does not supply a mainnet launch date.
