I have been running 17.04 using Gnome on Wayland for several months now without any problems. When I answered yes to the update to 17.10 on Wayland nothing happened (a warning about not being able to open an X window appeared when I used the terminal) so I updated to 17.10 on Gnome on Xorg instead.
After the update I have three choices in the boot screen:
Gnome, Gnome unter Xorg, Gnome unter Xorg (this appears twice), Ubuntu, Ubuntu on Xorg, Ubuntu on Xorg (again this appears twice), Unity
All three versions boot up OK with some minor differences in the two Xorg desktops and the Unity is my old Unity desktop. If I launch the Gnome or Ubuntu desktop and run "echo $XDG_SESSION_TYPE" it simply answers "X11" as you would expect.
My question is why would 17.04 run perfectly well on Wayland but not 17.10?