Veyon does not have Wayland support, which is slated to be released
with version 5.x in about two and a half years ago. In the meantime,
when client machines are logged in with Wayland, the master cannot
view their screens etc. I would suggest that, until Wayland support
materializes, there be a configuration option which tells the display
manager to discourage Wayland sessions. This could of course come with
varying levels of stridency: forbid Wayland entirely, pop up a scary
Wayland warning, just make X11 sessions the default, etc.