Short bio: Computer Scientist, FOSS supporter (read more)
Tux Machines (TM)-specific
With Canonical's planned adoption of their in-house Mir Display Server over the next year rather than using an X.Org Server or Wayland, derivatives such as KDE-based Kubuntu continue to fear the change and what exactly the options will be.
KDE will not support Mir as long as it remains a one-distribution solution. With KDE not coming to Mir for the foreseeable future, Jonathan Riddell of Kubuntu started a new technical discussion about non-Unity flavors and Mir.
Basically, the options now for Kubuntu (and similar derivatives like the LXDE and Xfce versions) is to either use Mir, use Wayland and hope everything works out, or simply end of life the distribution.