Ethereum Core Developers Lock in Timeline for Year-End Glamsterdam Upgrade

The Ethereum Execution Layer Core Developers have finalized key milestones leading up to the next major network upgrade, Glamsterdam.

As summarized by @christine_dkim, the 223rd All Core Devs Execution (ACDE 223) meeting brought new clarity to Ethereum’s roadmap for the final stretch of 2025.

The developers confirmed the Glamsterdam upgrade proposal deadline for October 30, with final scope confirmation scheduled for November 27. This sets a concrete path toward the Fusaka mainnet upgrade in December, keeping Ethereum’s execution layer upgrades firmly on schedule.

Fusaka Upgrade Timeline Finalized

The headline takeaway from ACDE 223 is the Fusaka mainnet upgrade, now officially set for December 3, 2025.

This release will introduce blob parameter optimizations, scheduled in two phases, December 9 and January 7, 2026. These changes fine-tune how Ethereum handles blob data introduced during the Dencun upgrade, improving efficiency for rollups and large-scale data posting.

Before that, the Hoodi testnet will activate its Fusaka version on October 28, serving as the final pre-mainnet test cycle.

Developers confirmed that Holesky, one of Ethereum’s largest testnets, will shut down next week as resources shift toward Glamsterdam’s testing framework.

Glamsterdam Upgrade Details

While Fusaka focuses on optimizing blob mechanics, Glamsterdam represents Ethereum’s next big leap in execution efficiency.

The upgrade will introduce a multi-client testnet, focusing primarily on the Block Access List (BAL) proposal, an experimental feature aimed at improving how nodes access contract storage data.

BALs could significantly reduce redundant reads and streamline gas usage during complex contract executions, further optimizing transaction performance.

Developers described Glamsterdam as a “modular prep” upgrade, setting the stage for future Rollup integration improvements, execution-layer compression, and gas efficiency reforms.

New Proposals: Gas Precision & Deduplication Discount

Two new proposals stood out during ACDE 223 discussions:

•  EIP 8058: Gas Precision Optimization – Aims to refine how gas units are calculated and rounded in specific edge cases. This would make gas consumption measurements more precise and predictable for developers, reducing the risk of mispriced transactions.
•  Deduplication Discount for Contract Redeployment – A proposed mechanism to lower deployment costs for contracts that reuse identical bytecode. This could significantly reduce gas expenses for DeFi protocols, DAOs, and wallet infrastructures that frequently redeploy similar smart contracts.

Both proposals were well received but will likely undergo testnet evaluation during the Glamsterdam phase before any mainnet inclusion.

Retired Proposals: EIP 7667 and 6873

Two previously discussed proposals, EIP 7667 and EIP 6873, were officially removed from the active roadmap due to overlapping priorities and changing design goals.

Developers noted that both proposals may be re-evaluated in future cycles if they align better with post-Glamsterdam objectives.

The decision reflects Ethereum’s ongoing commitment to refining roadmap scope, ensuring upgrades focus on tangible improvements to performance and developer experience rather than experimental expansion.

Developer Momentum and OKX Ventures’ Take

Ethereum’s development pace continues to accelerate into 2026. From Dencun’s blob integration to Fusaka’s optimization phase and Glamsterdam’s structural upgrades, the network is building toward a leaner, more modular execution layer.

OKX Ventures shared insight following ACDE 223, describing the next upgrade cycle as “a critical phase for Ethereum’s modular evolution.”

“Ethereum’s core upgrades are accelerating into a critical phase. From Fusaka to Glamsterdam, developers are continuously improving execution-layer efficiency and developer experience. These foundational upgrades will pave the way for modular scaling, rollup optimizations, and innovations in the application layer,” the firm wrote.

The comment underscores how closely infrastructure investors are tracking Ethereum’s low-level development, viewing these upgrades not as isolated patches, but as coordinated steps toward long-term scalability.

What It Means for the Ecosystem

The Fusaka and Glamsterdam phases are designed to prepare Ethereum for the next stage of Rollup-centric scaling.

•  Blob parameter tuning will make Layer 2 data submissions cheaper and more efficient.
•  BALs and gas precision updates will smooth execution logic and cut redundant costs.
•  Deduplication incentives will reward developers building on efficient contract design patterns.

Each step strengthens Ethereum’s execution layer, the part of the network responsible for processing smart contracts and transactions, setting a stronger foundation for long-term Layer 2 interoperability.

For builders, this means faster feedback cycles, lower deployment costs, and more predictable performance across networks.

For users, it means cheaper transactions, fewer network spikes, and a smoother experience on dapps built atop Ethereum.

Ethereum Market Context

At the time of writing, ETH trades at around $3,925, with a market cap of $473 billion, according to CoinMarketCap.

Price volatility around these updates remains minimal, reflecting how technical upgrades have become normalized within Ethereum’s predictable development cadence. However, as testnet launches begin in late October and November, community attention will likely return to performance metrics and upgrade testing outcomes.

With the Glamsterdam proposal deadline set for October 30 and final scope locked by November 27, Ethereum’s developers are entering a crucial execution window.

The Fusaka mainnet release on December 3 will act as both a closing chapter for 2025 and a stepping stone into 2026’s upgrade path.

Each stage continues Ethereum’s multi-year transition from a monolithic blockchain into a modular, rollup-first network, balancing decentralization with execution speed.

For now, all eyes are on Hoodi testnet’s activation on October 28, marking the last rehearsal before Ethereum’s next live performance.

Disclosure: This is not trading or investment advice. Always do your research before buying any cryptocurrency or investing in any services.

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