Ethereum’s Glamsterdam upgrade is approaching an important Sepolia trial after Prysm released a last-minute validator-client update to prepare for a sharp increase in block capacity.

Prysm, one of the main software clients used by Ethereum validators, issued version 7.2.1 late Monday. The release is designed to automatically set Sepolia’s maximum block gas limit at 200 million once Glamsterdam activates, replacing the 60-million-gas limit associated with the previous version.

The software change came just hours before the scheduled test because validators using the older client could have continued producing blocks at the lower limit. That would have undermined the purpose of the experiment, which is intended to evaluate Ethereum’s ability to operate with substantially larger blocks.

Glamsterdam is expected to activate on Sepolia at around 13:53 UTC on October 6. Validators running Prysm 7.2.1 should then begin proposing blocks using the 200 million gas limit.

Sepolia to Test More Than Three Times the Previous Capacity

Sepolia is being used as the first testing ground for Glamsterdam, Ethereum’s next major upgrade. Developers use the network to rehearse protocol changes without putting real-value funds at risk.

The October 6 experiment will increase Sepolia’s gas limit from approximately 60 million to 200 million.

Gas is Ethereum’s measure of computational work. Raising the limit allows each block to contain more transactions or more resource-intensive operations. The downside is that validators must process and propagate larger amounts of data, increasing the hardware and operational requirements for running the network.

Ethereum has been pursuing higher block capacity through incremental testing. Rather than immediately imposing a much larger limit on mainnet, developers are using test networks to determine whether validators can handle the additional workload without making participation prohibitively difficult or expensive.

A successful capacity increase could eventually give Ethereum more room for trading, stablecoin transfers and other applications. More available block space could also reduce competition for transactions during periods of heavy network activity and help contain fee increases.

No Immediate Change to Ethereum Mainnet

The 200 million gas limit applies only to Sepolia at this stage. Ethereum mainnet remains on its existing configuration, and Glamsterdam has not yet been deployed there.

The upcoming test will help developers determine whether validators can consistently support blocks exceeding three times Sepolia’s previous default capacity.

Its results will inform decisions about the appropriate block capacity for Ethereum’s main network. Until those decisions are made, the 200 million gas limit should be viewed as a testing parameter, not a confirmed mainnet target.