Final Devnet Testing Underway Ethereum $ETH developers have moved into the final testing phase for Glamsterdam, a sweeping network upgrade that core developer Parithosh Jayanthi described as
Ethereum $ETH developers have moved into the final testing phase for Glamsterdam, a sweeping network upgrade that core developer Parithosh Jayanthi described as "probably the largest fork we've had since the Merge." The upgrade is expected to reshape core assumptions about how the network operates and set the stage for significantly greater scalability.
Glamsterdam's final testing phase sees developers running all planned changes through private developer networks, known as devnets, before the upgrade moves to public testnets.It follows the Fusaka upgrade, which launched in December 2025.
The upgrade simultaneously updates the Execution Layer (Amsterdam) and the Consensus Layer (Gloas) to introduce Enshrined Proposer-Builder Separation (ePBS) and Block-Level Access Lists (BALs).These changes move block production rules directly into the protocol and enable parallel transaction processing.
Glamsterdam also overhauls how Ethereum prices state growth, via EIP-8037 gas repricing, in addition to the core ePBS and BAL changes.By increasing efficiency and potentially raising the gas limit to 200 million, the upgrade is projected to reduce Layer 1 gas costs significantly.
While the recent on-time delivery of the Pectra and Fusaka upgrades suggests Ethereum's development cadence has improved, Glamsterdam's broader scope and the complexity of ePBS mean the timeline could realistically slip into Q3 or Q4 2026.The Ethereum Foundation noted in April 2026 that ePBS proved more complex than initially anticipated, as handling edge cases between builders and proposers was not straightforward.
Core developers have been explicit that the path to mainnet runs through iterative devnets, stabilization, security review, and then testnet readiness before a mainnet fork date is announced.
Sources:CryptoTimes: Ethereum's Glamsterdam Upgrade Enters Final Testing PhaseFigment: What Glamsterdam Means for Institutional StakersEverstake: Ethereum Glamsterdam Upgrade Explained
