Glamsterdam Testnet Date Set: What Ethereum Builders Know
Ethereum's Glamsterdam upgrade was scheduled for the Sepolia testnet on 6 October 2026. See what it changes, what is unconfirmed and what builders can do.
Ethereum's next hard fork, Glamsterdam, was scheduled to activate on the Sepolia testnet on 6 October 2026 at 13:53 UTC, and press reports say it did. The Ethereum Foundation's Protocol Announcements page lists a "Glamsterdam Testnet Announcement" dated 28 September 2026, and the ethereum.org roadmap names the Sepolia fork as the next milestone. We could not open the pages directly and relied on press coverage, so check them for the final status.
Mainnet has no confirmed date. The target is Q4 2026, and that is a target, not a promise.
What is Glamsterdam?
It is the upgrade that follows Fusaka, which went live on mainnet on 3 December 2025. Coverage describes three main areas:
- ePBS (enshrined proposer-builder separation): building the split between block proposers and builders into the protocol.
- Block-level access lists: a record of which state a block touches, which can help clients process blocks in parallel.
- Gas repricing: changes to what operations cost.
Sepolia is reportedly testing a 200 million gas limit, more than three times the current mainnet limit. Treat that as a test setting, not a mainnet decision.
What is the schedule?
- Sepolia: 6 October 2026 (scheduled, reportedly activated).
- Hoodi: provisional for 27 October 2026, per secondary reporting.
- Mainnet: Q4 2026 target, no date.
Dates for Ethereum upgrades have slipped before. Earlier reports pointed to the first half of 2026, which shows how much these estimates move.
Why does a testnet fork matter to you?
Testnets are where client teams and app developers find problems before real money is involved. If you run infrastructure, wallets or contracts on Ethereum, the Sepolia fork is your first realistic chance to see how the changes behave. Gas repricing in particular can change how much a transaction costs your users, so a contract that was fine yesterday deserves a second look.
Projects that depend on tooling from third parties should also ask those vendors when their libraries and node software will support the new rules. Waiting for mainnet to ask is the expensive way.
What should builders do?
- Deploy and test your contracts on Sepolia after the fork.
- Re-check gas assumptions, especially for heavy operations.
- Read client release notes before upgrading nodes.
- Follow the Foundation blog, not social posts, for final dates.
This is technical information, not investment advice, and says nothing about prices. More guides are in the crypto and Web3 hub, and you can list your project in Discover.
