Ethereum's Glamsterdam Upgrade Enters Final Testing Phase

The Ethereum network's next major upgrade, Glamsterdam, has entered its final development phase, with core developers now testing the complete set of protocol changes in private environments ahead of a public rollout expected in the second half of 2026. This upgrade is described by developers as the most substantial modification to Ethereum's base layer since the network transitioned to a proof-of-stake consensus mechanism in September 2022.

Developers are currently operating private development networks, or devnets, which incorporate all planned Ethereum Improvement Proposals (EIPs). Parithosh Jayanthi, a core developer and DevOps engineer at the Ethereum Foundation, confirmed the milestone, stating this is the last phase before the code is hardened and deployed to public testnets. While a firm mainnet activation date has not been set, current projections point to a launch in the latter part of this year.

Jayanthi characterized Glamsterdam as probably the largest fork since the Merge, adding that it will change a lot of assumptions about Ethereum and set the network up for much more scaling in the future. The upgrade follows the Fusaka upgrade, which launched in December 2025...