Layla Zulfa
The Ethereum network is on the cusp of significant evolution, with the Fusaka upgrade slated for activation on December 3rd, 2025. This pivotal development marks the culmination of extensive testing and paves the way for future enhancements, including the ambitious Glamsterdam upgrade in 2026 and the subsequent Heka/Bogotá fork. These planned network upgrades underscore Ethereum’s continuous commitment to scalability, security, and decentralization, driven by a refined, more structured development process that aims to balance rapid innovation with network stability. The vibrant core developer community, closely watched through weekly All Core Developer (ACD) calls and summarized by resources like Forkcast, is currently navigating a complex landscape of feature prioritization, timeline management, and community feedback, particularly as the industry gathers for Devconnect week, potentially accelerating key decisions.
Fusaka: A Milestone Upgrade for Data Availability and Efficiency
The Fusaka upgrade, identified by EIP-7607, is set to go live on the Ethereum mainnet at 21:49 UTC on December 3rd, 2025. This highly anticipated activation follows a remarkably smooth testnet deployment, where Fusaka and its accompanying EIP-7892 Blob Processing Optimization (BPO) forks successfully launched across all three major testnets with minimal issues. This smooth transition stands in stark contrast to the complexities often observed in previous Ethereum upgrades, indicating a maturing development and testing infrastructure. While minor, non-consensus-critical issues are still being addressed by some client teams, these will not impede the scheduled mainnet rollout.
Fusaka’s primary objective is to enhance the network’s data availability layer, a crucial component for the scalability of Layer 2 solutions. EIP-7607, the core of Fusaka, focuses on optimizing how data blobs are handled, laying foundational groundwork for future increases in network throughput. For node operators, updating their clients before the December 3rd deadline is imperative to maintain network compatibility. The Ethereum Protocol YouTube channel will host a live watch party to commemorate this significant event, fostering community engagement and real-time monitoring of the activation. Further details on Fusaka’s features are readily available on the official Ethereum blog and ethereum.org.
The Phased Rollout of Blob Processing Optimization (EIP-7892)
Beyond the initial Fusaka activation, a crucial element of this upgrade cycle involves the phased implementation of EIP-7892, the Blob Processing Optimization (BPO) forks. This EIP is designed to incrementally increase the network’s capacity for handling data blobs, directly impacting the cost and efficiency of Layer 2 rollups that rely on Ethereum for data availability. Node operators need only perform a single client update prior to Fusaka, as these releases contain the necessary configurations for all subsequent forks.
The timeline for these critical BPO forks is as follows:
| Event | Time (UTC) | Target Blobs | Max Blobs |
|---|---|---|---|
| Fusaka mainnet | 2025-12-03 21:49 | 6 (unchanged) | 9 (unchanged) |
| BPO fork 1 | 2025-12-09 14:21 | 10 | 15 |
| BPO fork 2 | 2026-01-07 01:01 | 14 | 21 |
The initial Fusaka mainnet launch will maintain the current target of 6 blobs and a maximum of 9. However, the first BPO fork, scheduled for December 9th, will raise these limits to 10 target blobs and 15 max blobs, representing a substantial 66% increase in target capacity. The second BPO fork on January 7th, 2026, will further elevate these to 14 target blobs and 21 max blobs, an additional 40% increase from the first BPO fork. This strategic, incremental approach allows the network to gradually adapt to higher data loads, reducing potential risks associated with large, abrupt changes. The increases are expected to significantly lower data transaction costs for Layer 2 solutions, making Ethereum’s ecosystem more attractive and scalable.
Glamsterdam: Shaping Ethereum’s Future with Enshrined PBS and BALs
With Fusaka nearly deployed, the focus of Ethereum’s core development community is rapidly shifting towards the Glamsterdam upgrade, tentatively scheduled for "some time in 2026." This upcoming hard fork is poised to introduce two major "headliner" features: Enshrined Proposer-Builder Separation (ePBS) and Block-level Access Lists (BALs). These features were selected in August 2025, following extensive deliberation.
ePBS is a critical step towards mitigating Maximal Extractable Value (MEV) by separating the roles of block proposer and block builder. This separation aims to reduce the centralization pressures currently observed in MEV extraction, thereby bolstering the network’s decentralization and censorship resistance. BALs, on the other hand, are designed to improve transaction efficiency and potentially simplify smart contract interactions by providing more granular control over resource access at the block level. Both features represent significant architectural shifts aimed at enhancing Ethereum’s core infrastructure.
The Glamsterdam upgrade is also notable for pioneering a more structured and disciplined approach to upgrade scoping. Following the experience with the Pectra fork in 2024, which became overburdened with features and had to be split, ACDE call facilitator Tim Beiko proposed a stricter framework for defining upgrade content. This new methodology, characterized by clear timelines and deadlines, has already yielded results, with 48 "non-headlining" features proposed by the October 30th deadline for Glamsterdam. Core developers and the broader community are now actively reviewing this extensive list, prioritizing features based on urgency, compatibility, and complexity. Community input is actively solicited on the Ethereum Magicians forum to ensure that user needs are adequately represented in the final selection.
The FOCIL Debate: Censorship Resistance and Future Upgrades
Among the hotly debated features for Glamsterdam is Fork-choice enforced Inclusion Lists (FOCIL), a critical censorship-resistance mechanism. FOCIL received exceptionally strong community support, initially earning it a "Considered" status for Glamsterdam, conditional on its development not significantly delaying the upgrade and its compatibility with ePBS and BALs. However, recent discussions during the All Core Devs (ACDC) calls have indicated a growing consensus to move FOCIL to the subsequent upgrade, Heka/Bogotá.
This proposed deferral is primarily driven by a desire to streamline Glamsterdam’s development, ensuring that the primary headliners (ePBS and BALs) receive undivided attention and are delivered without undue delays. Moving FOCIL to Heka/Bogotá, however, comes with a caveat: the community seeks a "credible commitment" for its inclusion in that future upgrade. This decision has significant implications, as censorship resistance is widely regarded as a fundamental value proposition for Ethereum. If FOCIL is indeed moved, continuous advocacy from developers and the community will be essential to ensure it remains a high priority and does not get overshadowed by newer, "shinier" features. The challenge lies in maintaining momentum for a feature slated for an upgrade two cycles away, preventing it from falling into a state of indefinite postponement.
Optimizing Network Capacity: The Gas Limit Increase
Parallel to the feature-rich upgrades, Ethereum is also progressively increasing its network capacity. With the Fusaka upgrade, the network’s gas limit will officially be set to 60 million. All client teams have confirmed their readiness for this change, and node operators are not required to take any special action beyond their routine client updates, as clients will default to the new 60M limit.
This increase follows the establishment of a robust framework by Nethermind, one of Ethereum’s client development teams, for safely assessing and targeting higher gas limits. This methodical approach is expected to lead to continued regular increases in the default gas limit, systematically expanding the network’s transaction throughput. A higher gas limit means more transactions can be processed within each block, potentially reducing transaction fees and improving overall network utility. While clients will default to 60M, savvy node operators retain the ability to manually configure their limits and signal support for even higher values, contributing to the decentralized governance of network parameters.
Looking Further Ahead: The Heka/Bogotá Upgrade
The Ethereum development roadmap is designed with a forward-looking cadence, allowing for the planning of one upgrade while another is actively being implemented. With Fusaka nearing completion, discussions for the Heka/Bogotá upgrade are set to commence in early 2026. Heka has been chosen as the star name for the consensus layer, and the portmanteau for the combined upgrade is still under community discussion. As anticipated from the FOCIL discussions, it is likely to be a frontrunner for a headliner position in Heka/Bogotá, reflecting its critical importance to the network’s ethos. This structured approach to parallel planning is intended to create a more predictable and efficient development cycle, reducing the "limbo" state for features and developer resources.
Analysis: Balancing Innovation, Speed, and Stability in Ethereum’s Evolution
The current phase of Ethereum’s development vividly illustrates the ongoing tension between two strategic priorities: "ship safe" versus "ship fast." The Fusaka upgrade, launching approximately 6 months and 26 days after Pectra, demonstrates a tangible shift towards prioritizing speed. This accelerated timeline was partly facilitated by Fusaka’s major features having a head start in implementation, as they were originally part of the Pectra upgrade before it was split. This suggests that while a push for faster forks exists, practical factors such as prior development work play a significant role in achieving quicker delivery.
The new, structured process being piloted with Glamsterdam is a direct response to past challenges, particularly the "overburdened" nature of the Pectra fork. The aim is to introduce greater predictability, reduce chaos, and enhance efficiency in the upgrade cycle. If this new framework proves successful, its most profound impact may not be merely in accelerating individual upgrades, but in enabling better long-term planning and the potential for parallelizing the planning and development phases of future forks more effectively. This could lead to a more streamlined and continuous delivery pipeline for network enhancements.
However, the risk of "feature creep" and an "anything is possible" mindset remains a challenge. If Glamsterdam, despite its new structure, still feels as overwhelming as previous upgrades, it will necessitate a re-evaluation of how to manage community enthusiasm and temper the desire to incorporate a vast array of features into a single fork. The deferral of FOCIL to Heka/Bogotá is a prime example of this balancing act – a recognition that while a feature is highly valued, its inclusion must be weighed against the broader goals of a timely and stable upgrade.
The decision regarding FOCIL also highlights the inherent difficulty of making definitive commitments for features two forks into the future. Historical precedents show that community priorities can shift, potentially rendering prior commitments problematic. Therefore, for FOCIL to genuinely become a cornerstone of Heka/Bogotá, sustained and active support from both developers and the community will be crucial. Censorship resistance is a core tenet of Ethereum’s fundamental value proposition, and it is imperative that its urgency is not diminished by the allure of other compelling, yet potentially less critical, innovations.
Community Engagement and Developer Insights
The ongoing Devconnect week presents a unique opportunity for in-person discussions among core developers, potentially accelerating consensus on Glamsterdam decisions, particularly regarding minor features and the final status of FOCIL. However, the schedule also sees the cancellation of the next two Monday Testing calls, indicating a temporary shift in focus towards in-person collaboration.
For those keen to follow the intricate developments of Ethereum’s core protocol, the "Checkpoint" series offers high-level updates every 4-6 weeks, providing a digestible overview of complex discussions. Furthermore, Forkcast remains an invaluable resource, publishing comprehensive summaries, chat logs, and transcripts of each All Core Devs call, often within hours of their conclusion. These resources are critical for maintaining transparency and enabling broader community participation in the ongoing evolution of the Ethereum network. The period from October 2nd to November 13th has been particularly active, with numerous All Core Devs Testing (ACDT), Consensus (ACDC), and Execution (ACDE) calls shaping the path forward, as detailed in the relevant call archives on Forkcast.
