Ethereum’s Glamsterdam upgrade has moved deeper into multi-client devnet testing, with core developers coordinating execution and consensus-layer changes ahead of broader public testnet deployment. The upgrade remains planned for H2 2026, according to ethereum.org’s official roadmap page.
Ethereum Foundation materials frame Glamsterdam as a base-layer scaling upgrade focused on reorganizing how Ethereum processes transactions, manages state growth and creates and verifies blocks. That makes the current devnet phase important because the work now centers on cross-client compatibility rather than isolated feature design.
Ethereum Foundation Frames Glamsterdam Around L1 Scaling
The Ethereum Foundation’s 2026 protocol priorities identified ePBS, EIP-7732, repricings and block-level access lists under EIP-7928 as part of the Glamsterdam scaling track. The same update said gas-limit increases depend on execution-engine performance, client benchmarking and related consensus and networking work.
A later Ethereum Foundation protocol update from May said core developers had used an interoperability gathering to harden Glamsterdam. The post highlighted a multi-client Glamsterdam devnet with external builder testing, alongside work on block-level access list optimizations and EIP-8037 repricing.
Those details support the broader reading that Glamsterdam is not a single patch. It is a coordinated fork package aimed at increasing L1 capacity while preserving validation safety and manageable hardware requirements.
At the architectural level, ethereum.org says the upgrade centers on three goals: parallelization, capacity expansion and sustainability. That means Glamsterdam is designed to prepare Ethereum for higher throughput by improving how clients understand state dependencies and validate larger blocks.
All Core Devs Testing Shows Scope Still Being Refined
The clearest recent direct development signal comes from All Core Devs Testing call #82, held on June 8, 2026. Its agenda listed bal-devnet-7, glamsterdam-devnet-5 and a glamsterdam-devnet-6 tracker for execution-layer specification updates.
The same ACDT notes listed next steps to get all consensus-layer clients included in glamsterdam-devnet-5 and finalize the scope for both layers in glamsterdam-devnet-6. That shows progress, but also confirms that the fork package was still being refined through testing.
The ACDT meeting summary also described stability issues in DevNet 5, including client bugs and unclear causes behind forking behavior. Developers discussed whether to keep DevNet 5 alive for debugging or relaunch under DevNet 6, showing that network readiness still depends on resolving multi-client integration issues.
For ETH holders, the upgrade does not imply wallet changes or balance adjustments. Validators and node operators, however, will eventually need updated client software once a public testnet path and mainnet activation schedule are finalized.
The more careful conclusion is that Glamsterdam has made meaningful technical progress, but mainnet timing and final feature boundaries remain provisional. The next milestones are devnet stabilization, public testnet deployment and coordinated client release targets.