The Xubuntu developers have officially confirmed that they will not replace the X.org server with Canonical’s Mir Display Server, for Xubuntu 13.10 Saucy Salamander.
Unfortunately, Mir has support only for the open-source graphics drivers, developed by Intel, Nouveau and Radeon. The Mir and XMir fans can still use Canonical’s display server, because it is available via both repository and as an Xubuntu running with Mir ISO image.
The Xubuntu developers aim to add Wayland support to XFCE.
The story so far: Ubuntu 13.10 Saucy Salamander will ship with Mir by default and XMir replacing the old X.org. While Kubuntu 13.10 refuses to switch to Mir, in order to use Wayland, the Lubuntu team has also announced on their official site that they will keep the old X.org server , until Lubuntu 14.04 is released.