Just got finished with my first WordPress 2.5 upgrade and I'm happy to report that everything (except a !@%$#%@ spotty internet connection which made the process take at least three times at long!) went smoothly. Contrary to my expectation, none of the plugins broke!

The admin interface certainly is different—it's better, but still odd after so many years with the old one. However, I love the new one click plugin auto-upgrade feature. It downloaded, unzipped, and installed the latest version of Akismet without any problems.

Update 2008-04-06: I also like the new "modal" window approach to file upload. While the old file upload tab on the "Write Page" page was definitely usable thanks to an <iframe> and JavaScript, the interface was still a bit clunky. The new UI is definitely faster and slicker.

Update 2008-04-07: While doing another upgrade (from 2.0.9 to 2.5) I broke my first plugin: Category Visibility. However, since I'm not sure what version (other than the 2.0 series) it was last compatible with, this may not be a 2.5 issue.

Update 2008-04-07: It appears that query_posts() (or at least the way I've always used it!) is broken in 2.5. More on this to follow…

Update 2008-04-09: query_posts() is not broken, but the Adhesive plugin is.

Jeffrey Barke is senior developer and information architect at theMechanism, a maxi-media firm in New York City and London.