I just managed to do a WordPress auto-upgrade for the first time in a while. When it didn’t work this time, I searched the WordPress support forums and found out that the .htaccess file had to be fixed for users of 1&1.
This blog is now running on WordPress 2.8.3. The Markdown plugin stopped working in a very strange way, so I updated to a different Markdown plugin. Then I had to change the “next/previous page” links, but now everything seems to work.
If you notice any errors on this blog, please let me know.