Ethereum may ship a smaller Glamsterdam upgrade because key features aren’t ready for the mid-2026 deadline

Ethereum developers are confronting the possibility of reducing the scope of the blockchain’s next major Glamsterdam upgrade to meet a mid-year deadline, according to Christine D. Kim, founder of Protocol Watch.

In a newsletter published on Friday, January 23, 2026, on X and Substack, Kim stated that developers had come to a hard realization during this week’s All Core Developer Consensus (ACDC) call that some of the feature set planned for the Glamsterdam upgrade may be incompatible with shipping by mid-2026.

The situation is reminiscent of challenges that plagued the previous Pectra upgrade.

“Some of my readers who have followed my newsletters from Pectra upgrade days may be groaning inwardly and thinking, ‘Not again!’” Kim wrote in her post.

Glamsterdam is Ethereum’s first major test of the new twice-yearly upgrade cadence the foundation introduced in 2025.

Glamsterdam is meant to come after Ethereum successfully implements its Fusaka upgrade and was intended to deliver critical improvements to the network’s fairness and processing capabilities.

What could happen if Ethereum’s Glamsterdam upgrade misses its deadline?

EIP 7732, known as enshrined proposer-builder separation (ePBS) Devnet-0, may see its scope reduced or removed from Glamsterdam if the deadline is missed.

This feature is highly anticipated because it aims to reduce manipulation and centralization risks in Ethereum’s maximum extractable value economy.

Developers agreed during the ACDC call to target interoperable implementations by the end of February, but highlighted that it may not happen within the set deadline.

The second major component, EIP-7928 for block-level access lists (BALs), would enable parallel processing capabilities to improve network throughput.

However, implementation work has been hampered by technical challenges across consensus layer client teams.

Ethereum Foundation protocol prototyping team lead Toni Wahrstatter reported that an engine API change was impacting consensus layer (CL) client implementations for EIP 7928.

According to Kim, no team has yet achieved a fully working implementation of partial cell proofs, a networking change required to support further blob capacity increases.

More complications came from stress testing conducted by the Ethereum Foundation’s EthPandaOps team in December.

Enrico del Fante, a developer at Consensys working on the Teku client, reported issues that it discovered in the Teku client during the stress test. However, he reportedly stated that his team is still working on mitigating the known issues.

Del Fante requested that the EthPandaOps team pause on further mainnet stress testing while they develop mitigations, and noted that the problems have slowed their work on Glamsterdam.

February deadline looms

Developers have not yet officially acknowledged a mismatch between Glamsterdam’s scope and timeline.

Kim noted that the developers recognized there may be an issue and agreed to address it by the end of February.

While the Nimbus and Lodestar teams have completed this preliminary work, other client teams are still updating their systems, according to developer Etan Kissling of Nimbus.

The delay in Glamsterdam may also affect the Hegota upgrade, which is supposed to come after the successful implementation of Glamsterdam.

Alex Stokes, co-lead of the Ethereum Foundation’s Protocol Coordination team, has encouraged proposal authors to present their ideas at upcoming ACDCs.

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