WordPress 3.4 changed the shortcode syntax for image captions. This isn't an issue for themes that don't make any changes to the caption functionality or for themes that instituted the changes correctly. Unfortunately, previous to this blog, I have been implementing complete overrides of the caption to output HTLM5 Figure/Figcaption code. This broke with the change to the core WordPress caption functionality. The fix just involves changing the custom caption function to use add_filter.[foot]Instead of, say, add_shortcode('wp_caption', 'function') and add_shortcode('caption', 'function') as I had been doing previously.[/foot] When I developed the theme for this site, I found out the better way to do it. Read "Improved HTML5 WordPress Captions" here.[foot]Interestingly enough, that is one of the most frequently visited articles on this site.[/foot] I'm actually a little surprised they haven't made the move to using Figure/Figcaption by default.