Canonical founder and Ubuntu godfather Mark Shuttleworth has announced that the controversial new Mir graphics stack will appear in the upcoming Ubuntu 13.10 "Saucy Salamander" release. Canonical announced the Mir project in March, stating that the classic X graphics system was out of date and Ubuntu needed its own alternative.
At the time of the announcement, many in the FOSS community expressed concern about Ubuntu abandoning the Wayland graphics system, which many Linux developers regard as the next-generation Free graphics system. Canonical, however, wanted a graphics system they could build to their own specifications. The Mir project is further evolution of the effort Canonical began with the  Unity desktop -- a quest for a system that is easily adaptable to a broad range of hardware and display systems so that the same tools and components will run on a smartphone, tablet, or desktop with minimal adaptation. If the Unity experience is any indication, Canonical stands ready to withstand significant criticism to forge ahead with their plan.
According to Shuttleworth, "We take a lot of flack for every decision we make in Ubuntu, because so many people are affected. But I remind the team -- failure to act when action is needed is as much a failure as taking the wrong kind of action might be. We have a responsibility to our users to explore difficult territory. Many difficult choices in the past are the bedrock of our usefulness to a very wide audience today."  
Ubuntu's twin sister, the KDE-based Kubuntu project, has already announced that it does not intend to follow Ubuntu to Mir but will, instead, retain X for the 13.10 release, then migrate to Wayland for future releases. The popular Gnome and KDE desktop systems both support Wayland, which recently rolled out the new Wayland 1.2 release.