Upgraded my blog package to serendipity 0.9.1. I have not noticed anything special yet. Hopefully everything will be working fine. One small discovering, I can set the default character set to UTF-8 under the Administration -> Congfiguration. Not hack is needed from now on.
I am also in the process of setting up a blog package for my personal use in my company. I tried nucleus since it was rated higher than serendipity. But after playing with it for a while, I really think serendipity is more superior. Probably because I am very familiar with it now.