Ethereum’s weekly All Core Developer calls are plentiful to follow, so this “Checkpoint“The series aims for high-level updates approximately every 4-6 weeks, depending on what’s happening in main development. See previous update here.
If you like reading major development updates, you may also want to learn that Forkcast Now publishes call summaries, discussions and transcripts for each All Core Devs call, usually available within a few hours of the call.
tl;dr:
THE Fusaka the upgrade is almost at the doorGlamsterdam is gaining momentum and its main implementation features and minor features are being decided. Discussions around the Heka/Bogotá upgrade will begin soon.
If you want to give feedback on what minor features should be included in Glamsterdam, now is the time. There is no consensus yet on whether the Anti-Censorship Transaction (FOCIL) feature will be permanently included or deferred to a later upgrade. If you want to deliver an important feature for Ethereum, you should start preparing your headliner proposed discussion on the Heka/Bogotá upgrade, which is expected to start in early 2026.
It’s Devconnect week! Slower progress than usual over the next two weeks is possible. On the other hand, in-person discussions could speed up the decision-making process regarding Glamsterdam.
Fusaka
Testing for this next upgrade is complete, with Fusaka and both BPO forks having successfully gone live on all three major test networks with very few issues. For historical context, the testnet forks went much smoother than they generally do with these Ethereum upgrades. Although some customers are still experiencing small issues, they are not critical to consensus and therefore will not delay the upgrade.
Fusaka will go live on December 3 at 9:49 p.m. UTC and watch party will be streamed from the Ethereum Protocol YouTube channel. Node operators must update before this date to remain compatible with the network after the upgrade. An overview of its features can be found in the mainnet announcement blog post and on ethereum.org.
Chronology
A note for node operators: the Client versions ready for Fusaka contain configurations for the following three forks. Only one update is required to properly track updates.
| Event | Time (UTC) | Target blobs | Maximum number of blobs |
|---|---|---|---|
| Fusaka Main Network | 2025-12-03 21:49 | 6 (unchanged) | 9 (unchanged) |
| **BPO range 1** | 2025-12-09 14:21 | 10 | 15 |
| **BPO range 2** | 2026-01-07 01:01 | 14 | 21 |
Glamsterdam
With the conclusion of Fusaka, the focus now shifts to future upgrades. Directly after Fusaka, Glamsterdam aims “some time in 2026”. Its major characteristics (“headliners”), Separation between applicant and manufacturer established (ePBS) and Block Level Access Lists (BAL) were chosen in August while minor (“non-headlining”) features are currently under debate.
When the Pectra fork was set in 2024, the upgrade schedule was quite flexible and the upgrade did not have a clear headliner, resulting in an overloaded fork that had to be split in two. In response to this, ACDE call moderator Tim Beiko proposed a clearer and stricter structure to define the scope of an upgrade in order to optimize the process.
This is the first upgrade made a clear schedule and deadlines from the start, which results in a much greater number of features offered than in the past. The deadline to submit non-headlining feature films was October 30, with 48 features proposed on time. Core developers and the community are currently reviewing this list to determine which of them should be prioritized. Features will be chosen based on overall need/urgency, compatibility with other features, and their complexity levels.
If one of these characteristics is particularly urgent for users of the main protocol, the Ethereum community is invited to ring to help core developers understand this need.
FOCIL
While the headlining process encouraged the community to choose a single feature each for the execution and consensus layers for the sake of simplicity, Forced Choice Inclusion Lists (FOCIL), which is a censorship resistance feature, saw exceptionally strong support and was moved to a conditional feature.Considered» status while the two chosen priorities have been moved to “Program” status. This was discussed as dependent on the progress of ePBS (the consensus layer functionality) and to some extent BALs (the execution layer functionality) and also requires that FOCIL not significantly delay the upgrade.
In all this week’s core developersthere was support for moving FOCIL to the upgrade that will follow Glamsterdam, Heka/Bogotá, conditional on a credible commitment, yet to be determined, for it to be part of this upgrade. This move will better inform developers about their availability to work on smaller features, so that they are not left uncertain about whether or not they will need to think with FOCIL in mind.
Chronology
There is no proposed timetable for Glamsterdam yet beyond “some time in 2026.” This will depend on the overall scope of features chosen and the advancement of the headliners. It is likely that the finalized package will be decided by the end of this year, then developers can focus on implementing and choosing the main features for the next upgrade.
It’s Devconnect Week, which means in-person conversations can accelerate consensus for next week, All Core Devs Execution call, but the next two Monday test calls are canceled.
Gas limit
All customers have confirmed their availability for 60 M by Fusaka. No action is needed from node operators beyond normal client updates before Fusaka – all clients will default to 60M. Expect continued regular increases to the default gas limit now that there is an established framework by Nethermind to think about the security limits to target. Node operators can always signal their support for higher values by manual configuration their limits.
Heka / Bogotá upgrade
With a now established cadence of planning one fork while we implement the other, we can begin discussing the main features of the Heka/Bogotá upgrade after Fusaka goes live. Heka was chosen as a star name and the coat rack is still under discussion. After this week’s All Core Devs call, we can expect FOCIL to be the favorite in the headliner selection process.
Fusaka has been subject to the tension between two priority shipping strategies: ship safely or ship quickly. The community has been pushing for faster forks and it shows in the decision-making: Fusaka will ship 6 months and 26 days after Pectra, in part because it prioritized speed more than in the past. Where the dates of previous forks were generally chosen based on when all customers are ready, Fusaka’s calendar looked more closely at the dates when most customers were ready.
Fusaka’s readiness had a unique advantage in that its core features were initially part of Pectra before the upgrade was split in two, so their implementation had a head start, in a way. I don’t expect to see the same speed in Glamsterdam, although I expect there will always be pressure to ship as quickly as possible.
If this new structured process pioneered in the Glamsterdam upgrade results in less chaos and stress, and more efficiency than that of Pectra, it seems clear to me that the biggest gain lies in the long-term planning and structure defined for each stage of the upgrade, rather than simply pushing developers to move faster, and we can then experiment with better planning and parallelized development for future forks.
However, if Glamsterdam still seems as overwhelming as Pectra initially, we’ll need to find a way to more effectively harness the enthusiasm for adopting a wide range of features and the “we can do anything” mindset from the start of an upgrade.
For FOCIL currently moving to Heka / Bogotá: it is tricky to definitively commit to a feature in an update two forks in the future. We’ve learned this in the past when a feature has been planned but the community abandons its desire to implement it, and it’s then an unfairly problematic process to have to remove it when the developers are planning to implement it and have already started working on it.
If they are moved to the next upgrade, the best thing the developers and community can do for FOCIL is to maintain active support for its early inclusion and not move to a shiny new major feature that could lessen the urgency understood. Censorship resistance is essential to Ethereum’s core value and it’s important not to lose sight of this if another cool feature gains strong storytelling.
Relevant ACD calls:
(October 2 – November 13)
ACDT: 61, 60, 59, 58, 57, 56
ACDC: 169, 168, 167, 166
ACDE: 224, 223, 222
