so can OS 5.8 xfce desktop be updated to the newer version? - The post was for Series 6x. This is something to try in a test machine, for fun, NOT to install on your main system as mentioned.
2) does the xfce desktop receive updates in OS 5.8 or do you update the xfce desktop environment only in new Lite OS'? - if there are any XFCE updates, they will come in Updates. There are no major XFCE upgrades released during a Series, unless they have been tested by Ubuntu and deemed ready. So only in a new Lite OS generally speaking.
I would like to know how this works with Linux Lite, does the desktop xfce software get updtated regularly within the OS or only when you create a new OS? - see previous answer.