Key Insights:
- Revisiting contracts with gas limits or fixed gas prices. Reviewing contracts based on gas price limits or gas prices.
- Testing applications against updated execution-client implementations prior to network activation.
- Updating infrastructure that depends on hardcoded gas assumptions.
Glamsterdam will activate on Ethereum’s Sepolia testnet on October 6 marking another step toward expanding the network’s processing capacity. The Ethereum Foundation confirmed the activation for 13:53:36 UTC as developers prepare protocol changes that target block production, transaction processing and gas accounting.
The upgrade combines Amsterdam execution-layer changes with Gloas consensus-layer improvements. However developers have not scheduled its activation, on Hoodi or Ethereum mainnet leaving Sepolia as the confirmed milestone.
Ethereum confirms Sepolia activation schedule
The Ethereum Foundation confirmed the testnet activation at epoch 353,024 and slot 11,296,768. The announcement follows weeks of testing involving execution and consensus client teams.
Earlier development networks exposed implementation bugs involving consensus finality and gas accounting. Consequently, developers continued testing before confirming Sepolia’s activation date.
The execution-specification team released its first mainnet fixture package containing Amsterdam changes on September 23. The package followed a review of 15 execution-layer proposals included in the upgrade.
Client developers have also issued compatible software releases ahead of the scheduled fork. Go Ethereum 1.17.6 includes Sepolia’s activation timestamp, while Besu 26.9.0 arrived September 25.
Sepolia operators must update both execution and consensus clients before activation. Otherwise, their nodes risk following incompatible network rules after the fork.
Ordinary ETH holders and Ethereum mainnet users require no immediate action. The October 6 event affects Sepolia rather than Ethereum’s main network.
Protocol changes target faster block processing
Glamsterdam introduces enshrined proposer-builder separation through EIP-7732. The proposal moves block-builder coordination and payments directly into Ethereum’s protocol.
Currently, specialized builders construct execution payloads and communicate with validators through external infrastructure. Under the new arrangement, proposers include builders’ commitments before receiving complete execution payloads.
🚨𝗟𝗔𝗧𝗘𝗦𝗧: Ethereum’s Glamsterdam upgrade is set to go live on the Sepolia testnet on October 6, marking the next major testing step before a broader rollout. pic.twitter.com/AfeaExTP3b
— DustyBC Crypto (@DustyBC) September 29, 2026
The protocol then manages builder payments and separates consensus validation from execution checks. This is intended to decrease the need for trusted middleware when creating blocks.
Furthermore, the builders will be subject to a payload timeliness committee to judge if they will disclose execution payloads and blob information quickly. The separation of these processes allows validators more time to validate execution information.
One of the other key changes is EIP-7928, which adds block-based access lists. These lists identify the accounts and storage locations accessed on blocks and also the changes to the state on transactions.
Changes might provide the capability to get the state from disk and perform some validation in parallel. Developers also expect more efficient state-root calculations, supporting Ethereum’s longer-term Layer-1 capacity goals.
Gas pricing changes raise compatibility questions
Beyond block construction, Glamsterdam changes how Ethereum charges for resource consumption. Several proposals adjust the costs associated with creating and accessing contract state.
EIP-8037 raises and separately measures state-creation costs. In the meantime, EIP-8038 updates the cost for accessing the state to incorporate usage of network resources.
Other ideas include changing the cost of transactions, calldata, access lists, and block gas usage. All of these changes may impact current applications and infrastructure.
The Ethereum Foundation has issued a warning to developers to not use fixed gas prices or hardcoded gas limits in contracts. These assumptions may lead to compatibility issues in the new pricing regime.
This is likely to necessitate updates to wallets, indexers, and gas estimators. The earlier tests led to the developers fixing the implementation problems before moving forward to public testnet activation.
The above requirements warrant the importance of Sepolia testing to determine if any compatibility issues are present prior to mainnet deployment.
Ethereum roadmap is not restricted to Glamsterdam anymore
Hood is the next expected public testnet phase, but is not confirmed to be activated. Developer discussions have tentatively identified October 27 as a possible target.
Developers plan to discuss whether Hoodi can proceed after reviewing Sepolia’s performance. Meanwhile, Ethereum.org places the mainnet upgrade in the fourth quarter of 2026 without confirming a date.
The Ethereum Foundation has also opened its bug bounty program to the upgrade’s specifications and proposals. Security researchers can report eligible vulnerabilities as compatible client implementations become available.
Hegotá follows on the development roadmap, with developers targeting 2027. Vitalik Buterin has said it could become Ethereum’s final conventional-looking fork before development shifts toward recursive STARKs, automated verification, and redesigned consensus systems.
The longer-term roadmap also includes quantum-resistant infrastructure. Ethereum’s protocol team has set a December 2029 target for quantum resistance across execution, consensus, and data layers.
For now, Glamsterdam’s immediate significance rests on its confirmed Sepolia milestone. It will be used to guide future testing, and Hoodi and mainnet have no finalized activation plans.
