Countdown is on... 13 days until F12 stable.

[Bruno Wolff III]

On Wed, Nov 04, 2009 at 13:07:59 -0800,
  Konstantin Svist <fry.kun at gmail.com> wrote:
> 
> Will there be a way to upgrade F11 to F12?

Yes. There are several. But typically you want to upgrade using an install
image or you want to use preupgrade.

> And if I don't like F12, will there be a way to go back to F11?

Not easily. Try using a live image to try out the things you need to work
to see if it is suitable for you. If not, no harm done. If thinks look good,
then an upgrade will be less risky for you.