Ethereum has scheduled its Glamsterdam upgrade to activate on the Sepolia testnet on Oct. 6 at 13:53:36 UTC, moving its next major scaling package into public-network testing before a future
Ethereum has scheduled its Glamsterdam upgrade to activate on the Sepolia testnet on Oct. 6 at 13:53:36 UTC, moving its next major scaling package into public-network testing before a future mainnet rollout.
SummaryThe Ethereum Foundation announced that Glamsterdam will activate at epoch 353,024 and slot 11,296,768. Hoodi and mainnet activation dates remain undecided, meaning the Oct. 6 event applies only to Sepolia.
The upgrade combines changes known as Amsterdam on Ethereum’s execution layer and Gloas on the consensus layer. Its largest additions change how blocks are built, how validators check them and how clients handle state during transaction processing.
Node operators on Sepolia need compatible versions of both their execution and consensus software before activation. Ordinary ETH holders and Ethereum mainnet users do not need to take action for the Sepolia upgrade.
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Glamsterdam introduces enshrined proposer-builder separation, known as ePBS, through EIP-7732. The change moves the relationship between block proposers and specialized block builders directly into Ethereum’s protocol.
https://twitter.com/DustyBC/status/2104876752707416094Today, block builders commonly construct execution payloads and communicate with validators through external infrastructure. Under ePBS, a proposer includes the builder’s commitment to an execution payload, after which the builder reveals the full payload.
Ethereum’s protocol then handles the payment between the builder and proposer. The Ethereum Foundation says the structure reduces dependence on trusted middleware for block-builder payments while separating consensus validation from execution validation.
Validators gain more time to verify execution payloads because the consensus and execution checks occur separately. A payload timeliness committee determines whether builders revealed their payloads and associated blob data within the required time.
Glamsterdam will introduce another major component through EIP-7928, which creates block-level access lists. The lists record which accounts and storage locations a block uses, together with state changes produced by transactions.
Ethereum developers say this allows clients to read state from disk and process parts of transaction validation in parallel, while making state-root calculations more efficient. The official roadmap describes Glamsterdam as an upgrade intended to prepare Ethereum for increased Layer-1 capacity.
As crypto.news previously reported, Ethereum developers had been targeting the Oct. 6 Sepolia fork while private devnet testing continued. The date was initially treated as conditional while developers worked through consensus and execution bugs uncovered in earlier tests.
The public testnet schedule has since moved beyond that tentative stage. Ethereum’s Sept. 21 All Core Developers Testing notes state that Sepolia is confirmed for Oct. 6 at epoch 353,024 and 13:53:36 UTC.
The Ethereum execution-specification team released its first mainnet fixture set containing Amsterdam changes on Sept. 23. Developers said the package followed an in-depth review of the 15 execution-layer EIPs included in Glamsterdam.
Client releases are arriving ahead of the fork. Go Ethereum version 1.17.6, for example, explicitly includes the Sepolia Amsterdam activation timestamp and instructs Sepolia node operators to upgrade before Oct. 6.
Besu released version 26.9.0 on Sept. 25, while Nethermind 2.0.0 arrived earlier in the month. The Foundation’s current release table lists compatible execution clients including Besu 26.9.0, Erigon 3.7.0, go-ethereum 1.17.6, Nethermind 2.0.0 and Reth 2.7.0.
On the consensus side, listed Sepolia versions include Lodestar 1.49.0, Prysm 7.2.0 and Teku 26.9.1, with more client releases expected as teams finish compatibility work.
Prysm operators face an extra configuration detail. Prysm 7.2.0 defaults to a 60 million gas limit after activation, while validators that want to propose blocks with a 200 million gas limit need to configure that setting through the newer proposer controls.
The upgrade reaches beyond block construction. Several included EIPs change Ethereum’s gas accounting to better match the resources consumed when contracts create or access state.
EIP-8037 raises and separately measures the cost of state creation, while EIP-8038 changes the cost of accessing state. Other proposals adjust transaction gas, calldata costs, access lists and block-level gas accounting.
Application developers therefore need to test contracts under the new rules. The Ethereum Foundation has warned that applications relying on fixed gas stipends, hardcoded gas limits or assumptions about how much gas remains during execution could require changes.
Earlier testing already showed why the process matters. As crypto.news reported, Glamsterdam devnets uncovered bugs involving consensus finality and EIP-8037 implementation, prompting client teams to continue testing before confirming the public fork.
Ethereum even launched a temporary testnet called Platåberget in August to give developers more time to test Glamsterdam behavior. The Foundation warned that software relying on hardcoded maximum gas limits, including some wallets, indexers and gas estimators, could break without updates.
Hoodi is expected to be the next public testnet stage if Sepolia performs as expected. Developer meeting notes list Oct. 27 as a tentative Hoodi target, with a go-or-no-go discussion scheduled after the Sepolia activation, but the Foundation has not formally scheduled Hoodi yet.
Mainnet remains without an activation date. Ethereum.org currently places Glamsterdam in the fourth quarter of 2026 while explicitly noting that the date is unconfirmed.
The Ethereum Foundation has opened its bug bounty program to Glamsterdam specifications and EIPs. Client implementations become eligible as compatible releases are formally added, giving security researchers another route to report issues before mainnet deployment.
After Glamsterdam, Ethereum’s roadmap turns toward Hegotá in 2027. The next fork is expected to cover another set of protocol changes while developers work toward longer-term plans involving native account abstraction, stronger cryptographic verification and quantum-resistant infrastructure.
In related coverage, Vitalik Buterin said Hegotá could be Ethereum’s final conventional-looking fork before development increasingly moves toward recursive STARKs, automated verification, privacy and redesigned consensus systems.
Ethereum’s protocol team has separately set a December 2029 target for quantum resistance across the execution, consensus and data layers. The Hegotá roadmap currently includes work tied to that longer-term transition, although many individual proposals remain under review.
For Glamsterdam, the next fixed milestone is Sepolia at 13:53:36 UTC on Oct. 6. Node operators running Sepolia must install compatible execution and consensus clients before that activation or their nodes will no longer follow the upgraded network rules.
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