Ubuntu 27.04 may bring a preview of the long-awaited Core Desktop

It's a few years behind schedule, but development has resumed on the desktop edition of Canonical's existing immutable IoT distro, Ubuntu Core.

Engineering veep Jon Seager announced that Canonical is Accelerating Ubuntu Core Desktop on the company's Discourse forum. Even before his announcement, there was some fresh activity on the project's GitHub.

The post gives some explanation of why the effort is running so late, envisions three potential use cases, and talks a little about the work that is already going on to enable it to finally happen. There's no solid timeline given, but Seager says that "over the coming release cycle" the team will be working out what needs to happen, which means that "over the coming weeks, we'll have the infrastructure ready for… daily image builds for Ubuntu Core Desktop."

"Accelerating" sounds good, but with the best will in the world, it could hardly slow it down. In mid-2023 it looked like Desktop Ubuntu Core would arrive in 2024, and at that year's Ubuntu Summit in Rīga, Latvia, it revealed more details. At the 2024 Summit, there was a talk about a KDE version – but no release. At the 2025 Summit, the Reg FOSS desk interviewed Seager and "Where's Core Desktop?" was our first question.

The three roles his post discusses are the "browser-centric machine", a "developer workstation," and a "gaming machine." For this vulture, these goals imply two separate things. In general, this seems to indicate that it's wary of making something too specialized early on, then finding that it's not versatile enough for more challenging roles.

Secondly, we think that the company is thinking of three specific niches that rival immutable distros have occupied successfully for years. Right now, the "browser-centric" one is filled by ChromeOS and ChromeOS Flex. We use Flex – it's pretty good, even if its days are now numbered due to the new Android-based GooglebookOS.

Secondly, Fedora's Atomic editions have been around for years now – The Register first mentioned Fedora Kinoite well over five years ago. As well as Fedoras's own versions, there are also community-led distros based on the same tech, called Universal Blue. We've tried several, and while for now they offer nothing much this vulture wants, they undeniably work and they have happy users. Fedora's marketing aims at developers, and an immutable distro with containerized environments on top is harder to accidentally break with crashy work-in-progress code.

Thirdly, the games-machine niche is owned by Valve's SteamOS. Although it is native to the Steam Deck – and if you're among the lucky few, the Steam Machine and Steam Frame – you are also free to run this on your own AMD-based kit.

All three of these product families have been well-established for between five to ten years now. Canonical is lagging behind, and this is a subtle acknowledgement that it knows who the leaders are. We didn't doubt that he knows his stuff – a year ago, Seager’s blog post about The Immutable Linux Paradox went into the differences in depth.

The delay in delivering an immutable desktop is not for lack of immutable-distro technology: Canonical's had that for years. It announced Ubuntu Core 16 a decade ago, and when we tried Ubuntu Core, that was the fourth release.

Seager's post identifies some of the problems that have delayed its Core Desktop. One is that the 2023 preview required its own, specially modified version of the base core22 snap. Obviously, the company would prefer that it was based on the existing Core distro.

He also points to some essential underlying tech that is not obvious. He mentions that the Snap Store already has over 11,000 packages, but notes that many still use weak "classic" confinement – such as VS Code. This is a problem for Core, which requires strict confinement. He also notes some less-obvious things that need to work first, including smartphone-style permissions prompting, inter-snap dependencies, content snaps and snap components.

Some of the plans are ambitious, but in good ways. He discusses the need for modularity in the desktop snap packages, so that Core Desktop won’t be restricted to only GNOME. This means isolating the display manager (that is, the login screen) from the desktop, and the desktop from the browser. Here, he gives a nod to external consultancy enioka Haute Couture for its work on KDE snaps.

It's still much too easy to break any ordinary desktop Linux distro. In this vulture's extensive personal experience, the Btrfs filesystem is especially vulnerable. In four years of daily-driving a Btrfs-based distro in the 20-teens, we saw more crashes due to corrupted Btrfs volumes than in the previous two decades. However, all the vendors of Btrfs-based OSes are resolute in their denial about its real problems, which means they never get fixed. SteamOS and KDE Linux both use dual read-only Btrfs partitions, which update one another ChromeOS-style. This may be the only way to battle-harden this problematic filesystem. Canonical, on the other hand, offers integrated OpenZFS. We've been using ZFS since before the COVID pandemic, and it has yet to lose a single byte of data for us.

There are still blockers before Canonical can deliver a versatile, modular, desktop version of its existing immutable OS, but it's having another go. It's about time, and there is some new hope that we may start to see previews in the Ubuntu 27.04 timeframe. ®