Which Plesk do I have?
Windows: We are now provisioning new Windows Dedicated servers with Plesk 11.5. Plesk 10 may be found on previous dedicated servers as well. All Windows Shared environments are currently using Plesk 11.5.
Linux: Unfortunately Plesk is no longer offered at this time for any of our Linux plans. Legacy VPS servers with Plesk may have Version 10 or 11.5.