Ethereum’s next hard fork, Glamsterdam, went live on the Sepolia test network on 6 October 2026 at 13:53:36 UTC (epoch 353,024). It is the first public testnet to run the upgrade. Core developers have not set a mainnet date: the Ethereum Foundation says Hoodi and mainnet activations will be announced separately, and ETH holders have nothing to do for now.
What Glamsterdam changes
The name joins the two halves of the upgrade: Amsterdam on the execution layer and Gloas on the consensus layer. It follows Fusaka, the last fork to reach mainnet. The Ethereum Foundation’s testnet announcement, published on 28 September, lists 18 core EIPs. Three groups stand out.
- Enshrined proposer-builder separation (ePBS, EIP-7732). Today, most validators buy ready-made blocks from specialised builders through relays that sit outside the protocol. ePBS moves that split into Ethereum itself. In the Foundation’s words, “the protocol handles payment to the proposer, reducing reliance on trusted middleware”.
- Block-level access lists (BALs, EIP-7928). Each block declares which accounts and storage slots it touches, so clients can load data and process transactions in parallel instead of one by one.
- Gas repricing. Several EIPs raise the cost of operations that create or read state, and of calldata, so that fees track the real load on nodes more closely.
Smaller items include a log emitted for every ETH transfer (EIP-7708), a larger maximum contract size (EIP-7954) and a faster queue for validator exits and consolidations (EIP-8061).
The 200 million gas question
Glamsterdam is a scaling upgrade first. On Sepolia, validators can now opt in to a 200 million gas limit per block, up from a ceiling of roughly 60 million, Crypto Briefing reported. The defaults vary by client: the Foundation notes that Prysm 7.2.0 and Teku 26.9.1 stay at 60 million unless operators change their settings, and Prysm shipped a 7.2.1 patch around the fork. That 200 million figure is a test value. The gas limit that mainnet will use has not been decided.
A higher limit means more transactions per block, which over time should ease pressure on gas fees. Faster parallel processing through BALs is what makes a bigger block safer for node operators.
Why rollups care
Layer 2 networks post their data to Ethereum as blobs. Glamsterdam’s networking EIPs include a “sparse blobpool” (EIP-8070) and cell-level deltas for data column broadcast (EIP-8136), two changes to the way blob data travels between nodes. For a rollup, more room and cheaper execution on layer 1 also lowers the cost of settling back to Ethereum. Developers who rely on fixed gas assumptions in their contracts are told to review the repricing guide before mainnet.
What node operators and users need to do
- Sepolia stakers and node operators had to update both execution and consensus clients before activation. Supported releases include go-ethereum 1.17.7, Nethermind 2.1.0, Besu 26.9.0, Reth 2.7.0, Lighthouse 8.3.0-rc.0 and Prysm 7.2.1, according to the Foundation.
- Application developers are asked to test on Sepolia, especially anything touching gas accounting, logs or opcodes.
- Mainnet users and ETH holders have no action to take. Be wary of anyone asking you to “upgrade” or “migrate” your ETH: it is a classic scam.
The Ethereum Bug Bounty Program now covers the Glamsterdam specifications, and client code becomes eligible once a release is listed.
What to watch
The next step is Hoodi, the staking-focused testnet. ForkLog reported a tentative activation on 27 October, but the Foundation’s table still lists Hoodi as “TBD” and no date should be taken as final until it is announced. Mainnet comes after a successful Hoodi fork, and the final mainnet gas limit remains open. New to the network? Our guide What is Ethereum explains validators, gas and upgrades from the start.