The launch date for the next Ubuntu point release is being pushed back, but there's a silver lining: Canonical is promising fresher kernels in future builds.

The latest news coming out of Canonical is mixed. On one hand, it is delaying the release of 24.04.1, the first point-release of the current long-term supported version, April's Noble Numbat. However, the company is changing its kernel version policy to favor newer kernel releases for both interim and future LTS versions of Ubuntu.

Tackling the less pleasant news first, although the bulletin seems to mangle its dates a little, Ubuntu 24.04.1 was planned to be released this week, but it's been postponed by two weeks and is now expected on August 29. The company says that "a few high-impact upgrade bugs have been brought to our attention."

This isn't the first delay to hit the Noble release cycle. The beta version was two weeks late too. Also, for those bolder folks who eschew the every-even-numbered-year LTS releases and prefer the faster-moving, six-monthly "interim" releases, the option to update from 23.10 "Mantic" to "Noble" was similarly delayed back in May.

Note, that upgrade was only offered to people running the preceding interim release. If you are on an LTS release, as most Ubuntu users are, then you will only be prompted to upgrade when the following LTS gets its first point release. In other words, those running 22.04 "Jammy" don't get offered updates until the forthcoming 24.04.1, which will now be at the end of August.

As it happens, that's also the scheduled release date for 22.04.5. For now, that is the final point release on the schedule for "Jammy," but previous LTS versions have got to n.6 or even n.7 for Ubuntu 16.04 "Xenial" so there may be more to come.

Now with new, improved kernel freshness

The other recent announcement from Ubuntuland that will affect all users in future is, we feel, good news. The Ubuntu Kernel Team has announced a change in the way that it chooses what kernel version each specific Ubuntu release comes with.

Like Ubuntu itself, the upstream Linux kernel team offers two different types of finished release. Stable releases are finished, complete versions, released every two or three months, and getting frequent bug fixes until superseded by the next stable version. A lifespan in months is too fast for most distributions to keep up with, though, so there are also long-term releases. These are chosen roughly semi-annually and receive fixes for years thereafter… although not for as long as they used to.

(There are technically four channels. There are also two ever-changing work-in-progress versions: The mainline version, despite its safe-sounding name, is the in-testing build of the next stable release, followed by prepatch versions, which are release candidates. Both are best avoided except by kernel developers.)

The problem is that these two release cycles - that of the kernel and that of Ubuntu - are not in synchrony. (As it happens, Ubuntu's semi-annual release cycle was originally intended to sync with GNOME's six-monthly cycle.) The mismatched frequency is a problem for other distros too.

Stable kernels are only maintained for a few months, after which they're replaced with a new version - while interim Ubuntu releases are supported for nine months - and until 2013 it was twice that. Putting together a distro takes weeks of testing and integration, which means that when Canonical picks the latest stable kernel version for a new distro release, by the time that Ubuntu version is out, the kernel may be nearing its end of life. For instance, this happened with Ubuntu 22.10. This leaves Canonical maintaining end-of-life kernel versions for months.

As an example of the problem, since Ubuntu 24.04 came out in April, kernel 6.9 was released in May, and earlier this month was marked end-of-life, so users should upgrade to July's kernel 6.10. What will be Ubuntu 24.10 "Oracular Oriole" is still under development and will appear in October. Kernel 6.10 will be getting long in the tooth by then.

There is no easy way round this, and Canonical's new version selection process describes a quite complex set of stages of kernel maturity, with "Tight," "Unstable," "Bridge," and "Late" phases. The changed selection process distinguishes between two phases in the kernel development process of a mainline version. What Canonical terms an "unstable" kernel means either that the "merge window" is still open, and developers are still actively adding new code, or it's still in the early release candidate stage, which Canonical defines as RC1 to RC3. In what we feel is a pragmatic choice, a future kernel that is still this immature is too new and raw to be considered for a future Ubuntu release.

However, it's distinguishing these versions from Tight Releases, which are already at RC4 to RC6, meaning that new code isn't being added any more. With any luck, that means that specific kernel versions should be released before the next Ubuntu version reaches beta testing. So, if the next Ubuntu release hasn't reached Feature Freeze, Canonical will include these nearly ready kernel versions in its own development process, in the hope that the kernel will get to the final release stage before Ubuntu itself does.

The end result should be that not-quite-but-nearly-final kernels can be incorporated into work-in-progress Ubuntu builds, so that when they're released they end up with newer, supported kernel versions.

It will be interesting to see how this plays out. At The Reg FOSS desk, we'd like to see all the major periodic-release-cycle distros coordinate their releases with the upstream kernel team, and adopt "long-term" kernels just as Debian does. If that means commercial rivals must work together, that sounds good to us. They can do some extra legwork and work out how to share fixes while perhaps holding back feature improvements for their own products, and in the process, helping to fund the ongoing maintenance of the kernel. More cooperation would be good news for all concerned. ®

https://www.theregister.com//2024/08/19/ubuntu_240401_will_be_late/