Network upgrades on Ethereum do not flip a single switch worldwide. They activate at a scheduled slot after node operators have opted in by updating software. The next one on a public testnet, Glamsterdam, has now gone live on Sepolia.
According to the Ethereum Foundation Protocol blog, Glamsterdam was scheduled to activate on Sepolia at epoch 353,024, slot 11,296,768 — 6 October 2026, 13:53:36 UTC (14:53 London). [1] Ethereum community contributor Pooja Ranjan said it went live at that time, and CoinTelegraph reported the upgrade as live on Sepolia the same day. [2] Hoodi and mainnet dates are still undecided. This coverage is about Sepolia only.
A “testnet” is a practice network that mirrors mainnet rules without using real mainnet funds. A “hard fork” here means a coordinated protocol upgrade that nodes must support to stay on the upgraded chain.
What changed?
Glamsterdam combines the Amsterdam execution-layer upgrade with the Gloas consensus-layer upgrade. Its headlining changes are EIP-7732 (enshrined proposer-builder separation, or ePBS) and EIP-7928 (block-level access lists, or BALs), plus gas and state-pricing updates. [1]
In plain terms, ePBS builds the split between who proposes a block and who builds its execution payload into the consensus protocol itself, reducing reliance on trusted middleware for that exchange. BALs record which accounts and storage slots a block touches, so clients can read state and validate work more efficiently in parallel. [1]
Gas accounting also shifts. EIP-8037 and EIP-8038, among others, reprice state creation and state access. The Foundation warns that contracts which hardcode gas stipends or assume leftover gas may need testing and updates. [1]
Trade press also notes an opt-in push toward much larger blocks on Sepolia for the rehearsal, including a last-minute Prysm client fix so some validators would propose at a higher gas target rather than the previous default. That capacity test is specific to Sepolia and is not a mainnet gas limit. [3]
Who needed to act?
Sepolia node operators and stakers had to update both execution and consensus clients to releases that explicitly supported the scheduled Sepolia activation. The Foundation published Sepolia-compatible release tables in its announcement. [1]
Ordinary Ethereum mainnet users and ETH holders need do nothing for this Sepolia event. Mainnet will get a separate schedule when client teams decide dates. [1][2]
Why it matters
ePBS and BALs are foundational layer-1 scaling changes. They affect how blocks are built and validated and how clients parallelise state access—material for Ethereum engineering teams and for apps whose gas assumptions may change after the fork. Sepolia is one of the last major public rehearsals before teams set Hoodi and, later, mainnet dates. [2]
What we don’t know
- How the Sepolia rehearsal will score over the coming days on validator agreement, block propagation and app compatibility; early “live” reports are not a full post-mortem. [2][3]
- When Hoodi or mainnet will activate; both remain TBD in the Foundation’s announcement. [1]
- How widely application gas estimates will break after repricing; outcomes will vary by contract. [1]
The Bottom Line
Glamsterdam activated on Sepolia on 6 October 2026 as a scheduled testnet hard fork centred on ePBS, block-level access lists and gas repricing. Mainnet is not scheduled by this event. Treat Sepolia as a public rehearsal—not a mainnet go-live date.
Sources
- Ethereum Foundation Protocol blog, Glamsterdam Testnet Announcement, 17 September 2026 — https://blog.ethereum.org/2026/09/17/glamsterdam-testnet-announcement
- CoinTelegraph, Zoltan Vardai, 6 October 2026: report that Glamsterdam went live on Sepolia — https://cointelegraph.com/news/ethereums-glamsterdam-upgrade-launches-on-sepolia-testnet
- CoinDesk, 6 October 2026: report on the Prysm update and Sepolia capacity test ahead of activation — https://www.coindesk.com/tech/2026/10/06/ethereum-s-glamsterdam-test-gets-last-minute-fix-before-major-capacity-jump
