Denis de Benardy (the creator of the Semiologic Pro theme and many of the amazing WordPress plug-ins used here on How To Blog) sent off the following warning to his mailing list and kindly allowed me to quote him here:

Hello all,

I’m getting a rather large number of emails related to WordPress 2.1, so I figured I’d send this short notice.

Subtle yet very real changes occurred in the Database schema. Anything that relies on a post’s status (page/post, draft/published), in particular, is subject to hard to spot bugs. e.g. post lists, comment lists, etc.

A couple of options also disappeared with almost zero notice. Plugins that rely on them (and many do) will invariably be broken. Again, this may or may not occur with obvious bugs.

In the end, do NOT upgrade WP 2.1 immediately! There is no rush, as in security issues in need of fixing. And this update can potentially break many blogs if not dealt with properly.

A Semiologic Pro update with WordPress 2.1 will occur next week or so. But not before I feel things are stable enough for a proper release.

Thanks for reading!

Denis

He gives good advice…