10 to 11 upgrade

Got a client running 10, and I want to take them to 11. Is there anything special going to 11? I know going from 9 you have to clean install, but I should be able to upgrade from 10 to 11 - correct?

I will backup to be safe, but does the install give me to option to upgrade? I have not done this, and I can't seem to find documentation on doing 10 to 11. Any assistance would be appreciated.

Current version: Build: 10.2.1~svn20140618r37923release10.2-1squeeze
Going to latest download version

Thanks in advance