Prysm shipped the Sepolia gas schedule about 16 hours before the fork; without it, validators on older builds would have kept proposing at 60 million. The 200 million figure is a target proposers signal rather than a value the protocol enforces, and it applies to Sepolia alone.
Ethereum's Sepolia test network forked to Gloas at 13:53:36 UTC on Tuesday, raising the gas limit its validators default to from about 60 million to 200 million. The figure is one block proposers choose rather than one the protocol imposes, and the client release that made 200 million the default landed about 16 hours earlier.
The epoch and the fork time come from Prysm's release notes, which place the Sepolia Gloas fork at epoch 353024 on October 6 at 13:53:36 UTC. Crypto Briefing reported that the fork activated on schedule at that epoch.
Prysm published version 7.2.1 at 21:18 UTC on Monday. Its notes say the release "adds the Sepolia GAS_LIMIT_SCHEDULE, so validators default to a 200M gas limit from the Sepolia Gloas fork." From that publication time to the fork is 16 hours and 35 minutes.
CoinDesk reported that without the update, validators running older Prysm builds would have gone on proposing blocks at Sepolia's previous 60 million limit, which would have left a capacity trial with little extra capacity to measure.
A block's gas limit on Ethereum is not a constant written into the consensus rules. Proposers signal the limit they want, so a fork can make a higher ceiling available without any block using it. Crypto Briefing described the 200 million limit as opt-in, with validators able to signal a preference for it. Prysm's notes describe the same arrangement from the client's side, as a default. An operator who configures a different value gets that value instead.
Gas measures the computational work a block carries, so a 200 million limit admits more than three times as much of it per block as the roughly 60 million Sepolia ran before.
The 200 million target is not new to Glamsterdam's testing. Client teams were already running it on the multi-client devnet by late June, and the figure has been attached to the upgrade since developers settled its scope in April, alongside enshrined proposer-builder separation under EIP-7732 and block-level access lists under EIP-7928. What changed on Tuesday is that the limit reached a public test network with client defaults behind it.
Glamsterdam pairs an execution-layer fork named Amsterdam with the consensus-layer Gloas fork Sepolia has now taken. Crypto Briefing lists enshrined proposer-builder separation, block-level access lists and a set of gas repricings among its contents, and says earlier testing ran through the Platåberget and Devnet 8 environments. The Ethereum Foundation opened Platåberget in August to let wallets, indexers and gas estimators prepare for the upgrade's repriced gas, warning that it would break any tool with a hard-coded maximum limit.
"The 200 million setting applies only to Sepolia, and Glamsterdam has not yet activated on Ethereum's main network," CoinDesk wrote. Crypto Briefing reported that mainnet activation remains unscheduled and its final parameters undecided.
The same Prysm release carries other Gloas builder changes. Proposer settings files now take builder auth_data and builder_pubkeys as 0x-hex instead of base64, matching the keymanager API, and the default builder bid timeout rises to 600 milliseconds from 300. Cell-level dissemination of partial data columns becomes the default, with a flag to switch it off.
Glamsterdam is one step in a sequence Ethereum has set out for itself. Vitalik Buterin has described Hegotá, the fork after it, as the last normal one, against 2030 targets of four to eight second slots and finality in eight to 32 seconds.
What the Sepolia trial produces now depends on how many of its validators run the new default, and no figure for that has been published.
