As previously announced, the Canonical Kernel Team (CKT) has committed to target the Linux 6.17 kernel in the upcoming Ubuntu 25.10 (Questing Quokka) release as part of a more aggressive policy towards release kernel selection. With the recent release of Linux 6.16 we now have a much clearer idea of when 6.17 is likely to be released, as of this writing being tentatively Sept 28, 2025. The current 25.10 release schedule has Kernel Freeze set at Sept 25, which means that there is a strong possibility that Linux 6.17 will still be in a final -rc state at the time the kernel needs to be frozen for the 25.10 Final Release. Therefore, the CKT are announcing that Ubuntu 25.10 will potentially be an Unstable Release from the perspective of the kernel and will be henceforth working with that assumption until such time as conditions warrant a change.
The details on what an Unstable Release is as well as its ramifications and what you can expect can be found in the original policy post Kernel Version Selection For Ubuntu Releases, which has been recently updated to reflect refinements made over the last year.
Hello, what does it mean “Unstable Release”? Does it mean, that Ubuntu 25.10 will be released october 9 with bridge kernel 6.16 and that kernel will be later updated to 6.17 via update repository? Or does it mean, that release will be with 6.17 release candidate, which will be updated later to stable 6.17.x?
The terms are documented in the original description post, as well as the other details. For a brief summary, this post is to publicly announce that because of the proximity of the Ubuntu 25.10 and upstream 6.17 release dates, there is a good chance that the 25.10 release will ship with a kernel in a 6.17-rcX state and will upgrade to the formal 6.17 release once it is available. We may have to provide bridge kernels at 25.10 release but that will depend on what state upstream Linux 6.17 is in and we will not be able to make a final determination until much closer to the date.