upgrade version from 3.4 to 3.5

I want to upgrade my unity from 3.4 to 3.5, mostly because I want to use Game Draw. Anyway, Im hoping to keep my android licence for free, and I have the free unity version. Can i make the upgrade for free, or do I have to pay up the $400? If it is free, then how?

It’s a free upgrade from any 3.x to any later 3.x.