Kubuntu plans to steer clear of Mir and switch to Wayland
Kubuntu plans to avoid using Canonical's display server Mir and to instead continue using an X server for KDE on versions 13.10 and 14.04 LTS, after which the plan is to switch to Wayland, according to a blog post by Kubuntu developer Jonathan Riddell, formerly of Canonical.
Riddell mentions that it is not yet known what will happen if an Ubuntu user switches to a Kubuntu desktop or vice versa, saying that they'll "have to find a way to deal with that in a sensible manner". There could also be problems with maintaining Wayland support in Ubuntu's package repositories and already "fiddly" Live CD systems are a problem with just X, says Ridell, "never mind with three different graphics systems".
Kubuntu is following in the footsteps of KDE, which, just like Gnome, will also use Wayland in future. Some experimental support for Wayland is already available in the recently released first beta of KDE Software Compilation 4.11.