The Ethereum Glamsterdam upgrade on the Sepolia testnet is set for Oct. 6, ahead of the upcoming mainnet rollout with the more comprehensive scaling package on the network.
According to the Ethereum Foundation announcement, the fork will trigger at epoch 353,024 and slot 11,296,768. The activation is scheduled for 13:53:36 UTC on Oct. 6.
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The schedule only applies to Sepolia. The dates for Hoodi and Mainnet have not yet been publicly confirmed.
How ePBS Reshapes Ethereum Block Building
The Ethereum Glamsterdam upgrade packages both the Amsterdam upgrades on the execution layer and the Gloas upgrades on the consensus layer. The changes primarily involve block creation, validator checks, gas accounting, and state processing.
One of the largest additions is EIP-7732. Enshrines the “proposer-builder separation,” or ePBS, directly into Ethereum’s protocol.
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In the current model, specialized builders build the execution payloads and communicate with validators via external infrastructure. With ePBS, the full payload is not revealed until a builder has a commitment from the proposer.
Payment between the builder and proposer is then handled by the protocol. This mitigates the need for trusted third-party builder payment infrastructure, the Foundation claims.
The architecture segregates consensus validation and execution validation tasks, providing validators extra time to scrutinize the execution payload prior to full validation.
The payload timeliness committee monitors builder adherence to payload disclosure timelines and the release of blob data within designated periods, enabling the protocol to confirm timely receipt of block data within the required time window.
Ethereum Glamsterdam Upgrade Targets State Efficiency
Another significant proposal is EIP-7928. It builds block-level access lists that provide a list of accounts and storage locations that a specific block was used by.
The lists also record state changes that are generated by transactions. It can help developers access state from disk more efficiently, according to them.
The change also enables some checks that transactions can be executed in parallel. It could enhance state-root calculations during the upgrade to increase L1 capacity within Ethereum.
Some other proposals to alter the pricing of creating and accessing states on Ethereum. EIP-8037 raises and separately measures the cost of creating state.
EIP-8038 modifies the cost of accessing state. Changes to transaction gas, calldata pricing, access lists, and block-level gas accounting are among the other proposed changes.
These changes indicate that application developers must test with these new rules that impact contracts. The Foundation has cautioned software that relies on preset gas amounts or upper gas limits.
Some applications might require modifications, as they might be based on the assumption that a certain quantity of gas is remaining during the execution of the application. Developers are being asked to validate those assumptions prior to the broad-scale deployments.
What Sepolia Node Operators Need Before the Upgrade
The node operators on Sepolia must either upgrade to compatible execution and consensus clients or restart their nodes. This testnet event doesn’t require any action from regular ETH holders or Ethereum mainnet users.
Client teams have already started releasing software for the Ethereum Amsterdam upgrade. The Sepolia Amsterdam activation timestamp is included with Go Ethereum (Geth) v.1.17.6.
Besu is a Java-based, open-source full node, and each release of Besu has been announced on Sept. 25. Nethermind 2.0.0 has been available since the beginning of the month.
The Foundation’s current execution-client table also lists Erigon 3.7.0 and Reth 2.7.0. The releases are part of Besu, Go Ethereum, and Nethermind.
Consensus side support comprises Lodestar 1.49.0, Prysm 7.2.0, and Teku 26.9.1; further releases are forthcoming pending developer testing.
Prysm operators also need to review an additional configuration setting. Prysm version 7.2.0 sets a default gas limit of 60 million after post-activation.
Validator nodes seeking block proposals at a gas limit of 200 million need to enable the new proposer control settings prior to network activation.
Why Glamsterdam Needed Extended Devnet Testing
The execution-specification team also shared its first fixture set for major changes to Amsterdam’s mainnet on Sept. 23. The package came after a comprehensive review of 15 execution-layer EIPs, developers said.
The Oct. 6 date follows months of private devnet testing. Developers had previously treated the target as conditional while teams fixed bugs found in earlier trials.
This changed following the All Core Developers Testing session after September 21st. According to notes, Sepolia will launch at epoch 353,024.
A gradual adoption strategy is crucial because prior devnet testing revealed issues concerning consensus finality and implementation of EIP-8037.
Those issues pushed client teams to continue testing prior to locking in the public fork date. However, it also provided a chance for the developers to discover software assumptions that demonstrated that the new rules would not meet the intent.
Ethereum launched a temporary testnet called Platåberget in August. This network has allowed the research of developer behavior following the Ethereum Glamsterdam upgrade.
What Comes After Sepolia for Glamsterdam Testing
According to the Foundation, certain wallets, indexers, or gas estimators might break if they use previous maximum gas limits hardcodes. Those systems were advised to be updated prior to wider testing.
If Sepolia goes as planned, the next testnet phase will be Hoodi. A tentative date is Oct. 27 according to developer notes.
Since the Sepolia activation, a go-or-no-go conversation is expected to happen. Hoodi is not formally scheduled yet with the Foundation.
There is also no activation date for the mainnet. According to Ethereum.org, Glamsterdam is moving to the fourth quarter of 2026, which is currently listed as unconfirmed.
Client preparation and security testing are ongoing. The Foundation has now extended the Bug Bounty program to Glamsterdam specifications and to related EIPs.
Release implementations can become eligible as releases are formally added and found to be compatible. That provides yet another path for security researchers to exploit problems before they get mainstream.
What Hegotá Could Change for Ethereum
Following the Ethereum Glamsterdam upgrade, the roadmap focuses on Hegotá in 2027. Another set of protocol changes is expected in that fork.
The long-term roadmap for Ethereum development encompasses native account abstraction, robust cryptographic verification, and resilient quantum-resistant blockchain infrastructure.
The Ethereum protocol team has established a target deadline of December 2029 to achieve quantum resilience on its execution, consensus, and data layers. The Hegotá initiative is expected to support parts of that broader transition.
At the moment, the next fixed milestone is Sepolia. The Ethereum Glamsterdam upgrade is scheduled to take place at 13:53:36 UTC Oct. 6.
Before that time, node operators on the Sepolia network will need to install compatible execution and consensus software. Nodes that fail to upgrade will no longer follow the new network rules.
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