Ethereum’s Glamsterdam test gets last-minute fix before major capacity jump

Ethereum developers released an urgent update to the Prysm validator client ahead of a Sepolia test of the Glamsterdam upgrade, ensuring validators will propose blocks at a 200 million-gas limit. The Prysm 7.2.1 version, published late Monday, flips the client behavior so that when Glamsterdam activates on Sepolia, validators running the updated software automatically switch from the prior ~60 million-gas cap to the new 200 million setting. The change was time-sensitive because, without it or a manual configuration change, some validators would have continued producing blocks at the old 60 million limit. That mismatch would have diluted the test, which is intended to assess whether the network can handle a sustained increase in per-block computational capacity. Glamsterdam's Sepolia activation is scheduled for about 13:53 UTC on Oct. 6, 2026. The test raises Sepolia's gas limit to 200 million gas, giving developers a controlled environment to observe how validators and client software cope with block sizes more than three times larger than the previous default. Sepolia uses valueless tokens and serves as a rehearsal ground before changes are considered for Ethereum's mainnet. Ethereum teams have been incrementally increasing block capacity to find an upper bound where validator operation remains practical. The Sepolia trial is another step in that process: if validators can reliably handle the larger blocks, developers will use those observations to set appropriate capacity limits for the main network. The 200 million-gas setting applied in this test is specific to Sepolia and does not mean Glamsterdam has been enabled on mainnet.