Version 2.4 of the Semiologic Cache Plugin for WordPress has been released. WordPress sites running the Semiologic Cache plugin experience vastly improved site performance and this release improves upon that.
This version features enhanced Apache htaccess rules for better performance and overall user and browser experience. Additionally, the correct canonical url is now enforced when caching is enabled if the incorrect www or non-www version of the site’s url is used to visit the site.
Upon upgrading the plugin you will need to turn the cache off (Settings->Cache) then back on to force the new server rules to be written.