If you use the WP Super Cache plugin and want to upgrade, you must completely remove the old installation, otherwise you’ll get errors in your blog. At least, this is what happens with my installations. Follow this steps, loosely adapted from the plugin documentation:
- disable caching and disable the plugin;
- edit wp-config.php and delete the WP_CACHE define line;
- remove the files wp-content/wp-cache-config.php and wp-content/advanced-cache.php.
- remove the lines added by wp super cache in your .htaccess file;
- delete the wp-super-cache directory from /wp-content/plugins/, upload and unzip the new version
- go to the Plugins page and activate “WP Super Cache”;
- now go to Options->WP Super Cache and enable caching.;
- copy the mod_rewrite rulesÂ into your .htaccess file.
- check that /wp-content/cache/.htaccess has the two lines about gz