Jose, hello... I wish I could say definitely but I'm not sure how 1and1 licenses their resale of Plesk...
... ordinarly if you have a current SUS with Plesk I believe you'd be able to upgrade your key to the latest version when it's released.
I have a current SUS (software update service) for my Plesk licenses, direct from Parallels, which entitles me to the upgrades. I'm not sure if 1and1 does this or not. You may have to contact 1and1 and see...
Good luck!