Hi,
Did plextools not come with your drive? You can get it from there. Failing that check out
www.nero.com
Their free demo of "Nero" will allow you to see the version of your drive under "Recorder --> Choose Recorder" menu.
Good luck,
Andy
ps I think when you run the self extracting .exe firmware upgrade (available from
www.plextor.be) it tells you the current version before you flash.