Apologies for the bump, but after yesterday's SVN update, I'm seeing the "Unknown command: xgui" response.
Found an _xgui concommand, but it results in ...
Lua Error: [addons\ulx\lua\ulx\modules\xgui_server.lua:59 attempt to concatenate local 'name' (a nil value), but worry not, mortal, for Stickly Man is on the job.
Did not see any errors involving ULX/ULib (warnings about logString() being phased out, though) during bootup, but the wonderful little XGUI is ... dead.