I’ve been having issue with WordPress automatic upgrade for quite awhile. It never make any progress after download completes. This upgrade issue applies to both WordPress itself and its plug-ins. But at that time I’ve never bothered trying to find a solution for it. My WordPress version 2.6 was so far behind.
After searching on internet, the issue seems to relate to the PHP version. The service provider I using, 1and1, provides both PHP4 and PHP5. And WordPress seems to be confused when both are present. With a quick modification in the .htaccess file as shown below to make it use PHP5, the automatic upgrade for both WordPress and plug-ins are working again. Now I’m on the latest version.
AddType x-mapp-php5 .php
AddHandler x-mapp-php5 .php