I need to update a Plesk 9.5.4 server to Plesk 12. The installer tells me that I first need to upgrade to, at least, Plesk 10.4 before upgrading to Plesk 12. But, I can't find out how to upgrade from Plesk 9.5.4 to Plesk 10.4, only version the installer is showing is Plesk 12.