Ubuntu Shifting To A "4/2" Week Cycle For Shipping Stable Kernel Updates

Canonical has aimed to ship Linux kernel stable release updates (SRU) for Ubuntu releases on a three week cycle. That has worked out well overall but has led to delays at times in getting down CVE security fixes and other urgent customer requests. Moving forward Canonical is aiming for a new "4/2" week cycle for kernel SRUs.

Moving forward the aim is for Ubuntu kernel updates to be done on a 4-week update cycle while having a follow-on release at the 2-week midpoint to provide any critical/high CVE fixes or any other critical fixes. In effect, a kernel update every two weeks but that mid-point release will be reserved just for more urgent items that can't wait until the next 4-week release.

The announcement by Kleber Souza of the Canonical Kernel Team explains:

"In order to improve our kernel SRU release cadence velocity and predictability, the Canonical Kernel Team is transitioning from the 3-week cycle to a new 4/2 Kernel SRU Cycle. That is, a 4-week standard stable update cycle, containing the regular upstream stable updates as well as security and bug fixes and feature requests, combined with an additional planned update to be released at the 2-week midpoint of the following 4-week cycle. This “/2” update will contain only CVE fixes rated critical or high and/or other time sensitive critical customer fixes that are deemed unlikely to cause regressions.

With the new schedule, we are aiming to release fixes for critical and high CVEs and any other critical fixes on a 2-week cadence. The “/2” security/critical update being released on top of a previously released standard stable update cycle is to ensure the critical fixes are not held up by any issues/regressions in the new “4” stable cycle.

After the 2-week midpoint releases are published (at the beginning of the third week), there will be another opportunity window for re-spins in the 4-week cycle for regression fixes and/or additional urgent fixes. This mid-cycle re-spin is expected to be particularly useful for kernels that require quick turnaround times to meet project deadlines (e.g. OEM kernels)."

The full announcement for this shift in Ubuntu kernel updates can be found on the Ubuntu Discourse.