Ubuntu Wiki

Why is patch X not applied to Release Y?

It is not always possible to backport a fix to an older release. The key requirement for any changes applied to older releases is that they not introduce any regressions for other users. The fix may help your case but cause issues on other systems. This introduces risk in releasing fixes in older releases and may sometimes prevent us fixing your problem. Often we will only be able to fix these types of issues in the next release. This is outside the kernel team's control, see the StableReleaseUpdates and KernelTeam/KernelUpdates pages for details.