As of WordPress 2.3 the tables categories, post2cat, and link2cat have been removed. New tables replace them but they aren’t the same. WordPress is moving more towards tagging / taxonomy, which is fantastic. However, many plugins are still using the old table terminology. After I upgraded I did a search in all the plugins I used and disabled them until they get updated. One of them I don’t really use anymore as WP has the features I need to replicate it built in (customizable post listings) while I do want Google sitemaps back.
So, keep that in mind when upgrading that it might break some of your plugins if they do business with the categories, post2cat or link2cat tables.
[tags]Wordpress, Plugins, Upgrade, 2.3.x[/tags]
For Google sitemaps on 2.3.1, use this one:
http://www.arnebrachhold.de/projects/wordpress-plugins/google-xml-sitemaps-generator/
I’m using it and it works well.
Patrick