Ethereum's Glamsterdam upgrade activated on the Sepolia testnet on Tuesday at 1:53 pm UTC, marking one of the final major rehearsals before the protocol change reaches the Ethereum mainnet. Ethereum community contributor Pooja Ranjan announced the activation in a post on X.

The launch sets up a two-step endgame: developers will next determine Glamsterdam's activation date on the Hoodi testnet, then fix the date for its mainnet debut. No mainnet date has been set yet.

What does Glamsterdam actually change?

Glamsterdam is the next major Ethereum upgrade after Fusaka and, according to the Ethereum Foundation, one of the most consequential protocol changes scheduled for 2026. A Sept. 28 Ethereum Foundation blog post outlined its three structural pillars:

• Enshrined proposer-builder separation (ePBS), specified in EIP-7732
• Block-level access lists (BALs), specified in EIP-7928
• Gas pricing changes that better reflect the cost of execution

EIP-7732 enshrines the separation between block proposers and builders directly in Ethereum's consensus protocol. It also splits consensus validation from execution validation, which gives validators more time to verify execution payloads — a rearchitecting of how blocks are produced and attested to, rather than an incremental parameter tweak.

EIP-7928 introduces enforced block-level access lists that record which accounts and storage locations a block touches, along with post-transaction state changes. The operational consequence is concrete: clients can read state from disk in parallel, validate transactions in parallel, and compute state roots more efficiently.

Why parallelism is the headline

Ethereum currently runs in what developers describe as single-lane mode, processing transactions in a single order. The access-list machinery in Glamsterdam is designed to unlock parallel processing across clients, enabling higher transactions per second and bigger blocks without raising the gas limit.

The Foundation has also committed to a specific performance target. In a May blog post, it established a 200 million gas limit floor for Glamsterdam — more than three times the network's current gas limit of roughly 60 million — which would represent a substantial post-upgrade throughput increase for the layer 1.

What comes after Glamsterdam?

Once Glamsterdam activates on mainnet, Ethereum developers will begin implementing Hegotá, the next major upgrade. Scoping is already underway: in August, developers started reviewing 66 candidate proposals, with several targeting expanded privacy capabilities at the protocol level.

The immediate milestone to watch is the Hoodi testnet activation decision. A successful Hoodi run would clear the last technical gate before developers schedule Glamsterdam's mainnet activation, closing out an upgrade cycle that reworks block production, validation and gas economics in a single hard fork.