I was away on holiday, so perhaps I am a little late, but Serendipity 1.0 final is out!
“The Serendipity Team is proud to announce the final release version of Serendipity 1.0, an advanced and flexible blogging/cms web application. With its comprehensive feature set, including multiple authors, internationalization, templated output, and an open plugin architecture, Serendipity’s stable 1.0 release is ready to become the most popular Web application in the world!”
Upgrading (and installing) is easy as 1-2-3 
Give it a try.