VM Host Server upgrade is complete. Downtime was less than 10 minutes, much of which was disk checks on reboot. All systems go.
Although Mozilla Thunderbird may have a dated interface, it is a powerful and flexible email client. We use autoconfig on our DNS servers so that when you add your email address and password to the Account Settings, it should automatically find then add your settings auto-magically.
If this does not work, this is likely because your DNS servers are hosted elsewhere than the primary iThinc DNS servers and you'll need to set up the settings manually with the settings found on this page.