I wouldn't recommend upgrading with apt-get. I did it (very early) when PR1.1 came out. It didn't get all packages. One package in particular was missing. I can't recall the name of it, but it was some sort of meta package that pulled in a load of extra stuff in. I only found about it after being quite puzzled by the fact, that despite the upgrade my version number didn't change. After installing the meta package (and all it's dependencies) everything was fine and my version number was correct.

I'll see if I can figure out the name of that meta package...

EDIT: Found it. It's called "mp-fremantle-generic-pr".

I just ran "apt-get update && apt-get dist-upgrade" and there was nothing interesting to update.