I was on WP 2.8.6 and decided to upgrade P2 to the latest version that came out this evening (for me) - i.e. 1.1.1.
After upgrading P2, I realised that 1.1.1 is in fact only compatible with WP 2.9 beta and above. I wish I had read the release notes.
I upgraded WP to the latest beta 2.9 release and then followed this up with the latest nightly build. Unfortunately P2 still does not work as expected.
At the moment, I can see the new posting interface (new tabs) and a title of my last post (no post content) and just the sidebar. Nothing else is displayed.
I am not too sure what has gone wrong.
Please have a look at http://www.omarkassim.com to see what I mean - I may change this in a few hours if I can't get to a workable solution.