Canonical has made a change to Ubuntu's interim LTS releases (eg 20.04.1, 20.04.2, 20.04.3, etc.) to improve the quality of releases at the expense of meeting deadlines. Whereas previously interim releases were built exactly as planned, now priority will be given to the quality and completeness of testing of all fixes. The changes are based on the experience of several past incidents, as a result of which, due to the addition of a fix at the last moment and the lack of time to check, regressive changes or incomplete fixes of the problem surfaced in the release.
Starting with the August Ubuntu 20.04.3 update, any bug fixes categorized as release blockers made during the week prior to the scheduled release will move the release timeline, allowing the fix to be thoroughly tested and reviewed instead of being rushed. In other words, if a bug is found in release candidate builds, the release will now be delayed until all fix checks are completed. For early detection of problems blocking the release, it was also decided to increase the freeze time for daily builds from a week to two weeks before the release, i.e. there will be an extra week before the first release candidate is published to test the frozen daily build.
In addition, it was announced that the package base of Ubuntu 21.04 will be frozen from introducing new features (Feature Freeze) and shifting focus to the final refinement of already integrated innovations, identifying and eliminating errors. Ubuntu 21.04 release is scheduled for April 22nd.
Source: opennet.ru