I upgraded the blog to WordPress 2.6 last night – extra features in the latest WordPress include version history (could be useful for me as I tend to write a few drafts before publishing my longer posts), press this (a bookmarklet you can use to blog about websites etc.), picture captions, theme previews, and Google Gears support.
Upgrading is always a scary experience as I’m terrified I’ll lose my content (I didn’t actually do it myself this time, Chris helped me). Although all seemed fine initially, I soon realised that the front page was working but the individual posts weren’t showing (the message “Sorry, no posts matched your criteria” was displayed).
After a bit of investigating (i.e. Googling!) this morning, we found it is a known bug affecting anyone whose permalink includes index.php. Thankfully, the solution is simple. Details are given on the WordPress website but basically the easiest way to solve it is to add values into the category and tag fields in the permalink options page (the values can simply be the words category and tag). That should hopefully fix it, it did for me.
Apologies to anyone trying to view posts last night, but it should be back to normal now.