A look at Ubuntu Desktop LTS 24.04

Ubuntu 24.04 LTS, code-named "Noble Numbat", was released on April 25. This release includes GNOME 46, installer updates, security enhancements, a lot of updated packages, and a new App Center that puts a heavy emphasis on using Snaps to install software. It is not an ambitious release, but it brings enough to the table that it's a worthwhile update.

Ubuntu users expecting to upgrade to the new release right away are in for a bit of disappointment. The release notes indicate that upgrades from earlier releases are not yet supported. Users on the previous release, 23.10, will be offered an upgrade via Ubuntu's software and updates application when it is ready. Moving from 22.04 LTS will be supported when 24.04.1 is released in August. Those eager to jump right in are advised to make a backup of their data and do a clean install rather than attempting an upgrade.

Meet the new LTS

Starting with a fresh install will provide a chance to try out the latest version of the Subiquity installer, which now includes the ability to update itself before beginning an installation. If the system is connected to the Internet, Subiquity will check to see if there is an update available and (if so) apply it before proceeding. This can be quite useful for addressing bugs or adding new features after the installation media for a release has been distributed.

One interesting change in the installer workflow is the addition of a step to set up accessibility features immediately after the language is selected. This may be a helpful addition for users who need assistive technologies, when it's fully ready. The screen reader included with the installer is described in the release notes as incomplete and has a number of bugs indicating that it is currently not usable to perform the installation.

The disk partitioning step now offers TPM-backed disk encryption if the system has a compatible trusted platform module (TPM). The ZFS filesystem is also offered as an option, as it is in the 22.04.4 LTS installer, but is now marked experimental and is lacking encryption support. The option to install ZFS was disabled in the 22.10 release due to a bug that caused problems on first boot. Support for guided ZFS installation was re-added in Ubuntu 23.10 with a note that encryption would return in a future release. Aside from those changes, the workflow for installation is basically the same as the previous LTS release.

Desktop

"Basically the same" is a theme that carries through to the desktop, at least at first glance. Once installed, there's little visible difference between 24.04 LTS and the prior LTS release. A few icons have changed, the wallpaper sports the Numbat logo, and the button that used to be labeled "Activities" in the top-left corner is replaced with a pill-shaped icon. Like its predecessor, clicking that will bring up the activities overview that shows all of the open application windows.

One of the user-interface improvements Ubuntu attempted to drive in previous releases was a "Global" menu that integrated the application's menu with the top bar of the desktop rather than in the application's window, in a similar fashion to the user interface of macOS. However, Apple is able to enforce uniformity in its interfaces in a way that Canonical cannot. It was an interesting idea that could have saved a bit of screen space, but most applications did not support the feature so the menu would only include a few menu options such as "quit" and "new window". It has been entirely removed in this release, which is understandable but unfortunate. No matter how much screen space is available, a little more is always appreciated.

The desktop is mostly standard GNOME 46, which we covered in March, with a few additions, tweaks, and the omission of the GNOME Software application along with support for Flatpaks. GNOME Software and Flatpak can be installed with APT, but only if users know to go looking for them.

The rest of the changes are minor in comparison. For example, in Ubuntu alt-tab cycles between windows rather than applications. The desktop sports the Ubuntu Dock, which is similar to the GNOME Dash-to-Dock extension except that it can't be disabled. There is also an "enhanced tiling" feature that provides more flexible window-tiling options than standard GNOME. Dragging a window to the corner of the screen will cause it to snap into position taking up either one-half or one-quarter of the screen. (GNOME only allows two windows to be "tiled" side-by-side.) It's still limited compared to extensions like gTile that allow a wide range of tiling options, but it can be useful.

Ubuntu Desktop now defaults to a "minimal" install that leaves out things like games, a mail client, and office software. This is an interesting evolution (no pun intended) from the early days of Ubuntu. When the distribution first arrived on the scene, one of its distinguishing characteristics was providing an opinionated selection of software rather than asking the user to choose from a dizzying array of options at install time. Now users are given a nearly blank slate. This does make some sense—in the nearly 20 years since the Warty Warthog release, people depend a lot less on locally installed software. A browser and a handful of applications may be all that a person needs to be productive if much of their software is browser-based. For additional software, users can turn to the new Ubuntu App Center.

At first glance, it would be easy to conclude that the App Center only works with Snap packages. All of the software that users can find just by browsing the store is Snap-only. Debian packages are filtered out of searches. It would be unfair to say that the option of installing Debian packages is hidden, but it is easily missed.

Users who prefer to install software via the command-line will be mostly unaffected by the push toward Snaps. The exceptions include Firefox and Thunderbird, which are not available as standard Debian packages in the Ubuntu repositories. Instead, users who try to "apt install thunderbird" receive a dummy package that installs the Snap instead.

Of course, GNOME is not the only Ubuntu desktop flavor available. Users can opt for Budgie, Cinnamon, KDE, LXQT, Mate, or the Unity desktops. There are also use-case-specific options, Edubuntu for educational use, Kylin for Chinese users, and Studio for multimedia production.

Miscellaneous

Naturally, 24.04 has a great number of updated packages. It includes Linux kernel 6.8.0, systemd v255.4, LLVM 18, GCC 13.2.0 (with an experimental version of the unreleased GCC 14), GNU C Library (glibc) 2.39, and Binutils 2.42. Other changes include updates to Python 3.12 as the default Python, OpenJDK 21, Rust 1.75, Go 1.22, Ruby 3.2.3, and Perl 5.38.2.

The new Firmware Updater application is a nice addition, but it is something of a black box. It displays a list of system firmware along with upgrades (and downgrades) that can be applied, as well as options to update their checksums and to verify the firmware. Unfortunately, it doesn't provide links to the original download site for firmware or give the user any way to even see the checksums. Clicking "Verify Firmware" pops up a dialog that asks if the user wants to verify the firmware. Clicking "OK" just closes the dialog box without any indication whether the check was performed or if it passed.

There are a few security enhancements worth noting. For example, unprivileged user namespaces are now restricted to prevent potential kernel exploits. Because many applications, like Buildah, Firefox, Podman, Thunderbird, and others, use user namespaces, there are nearly 100 AppArmor profiles allowing well-known applications to use user namespaces. If an application isn't in that list, such as Bubblewrap, it's reasonably easy to create an AppArmor profile that allows the application to create a user namespace. It's also possible to disable the restriction entirely, though that hasn't proven necessary so far in my day-to-day use.

APT now expects RSA signing keys of 2048 bits or more, and will warn when trying to install packages signed with 1024-bit keys. The release notes indicate that the warning will become an error when APT 2.8.0 is introduced at a later date. (The current version is 2.7.14.)

Not entirely baked

There is certainly no rush for Ubuntu users to upgrade right now with standard support for 22.04 LTS through 2027. Numbat will receive standard security maintenance (in other words, free updates without requiring an account) through 2029. Those who have an Ubuntu Pro account can receive updates for 24.04 LTS through 2034. See the release cycle page for full details.

Overall, Noble Numbat is a good release, but it feels much less finished than one might expect for an LTS release. This may, in part, be because the release cycle was interrupted by the XZ situation. Canonical opted to delay the beta by one week and do a full rebuild of all packages, but stuck to the April 25 release date. An extra week (or more) to address bugs might have been in order. Ubuntu users who prefer stability over novelty may wish to sit out the upgrade until 24.04.1 is available later this year.