I am upgrading 9.10 to 10.4 Kubuntu (the 9.10 means 2009 and the month of October (10), so thus 10.4 means 2010 and the month of April).
It really could not be any easier just open up a quick run command
ALT + F2
and then type in
update-notifier-kde -dAnd it will do the rest for you, update – upgrade your system..
Not much more to say really apart from once I have updated I shall have to say what I think of the 10.4 LTS (Long Term Support) version. Which the LTS has 2 year release cycle, 3 years support for the desktop and 5 years for a server, that is just great!.