Hi Emmet! 

 

I tend to err on the side of caution and recommend that you first upgrade to version 7.x, then complete the upgrade to 15.x / 16.x. However, I've also heard multiple reports from customers of successful upgrades directly from 5.x / 6.x to the latest. There are file structure changes that took place in version 7.x, which is why we tend to recommend separating the process. However, if you decide to upgrade directly to 15.x and have trouble with your mailboxes, we do have a utility that will correct the file structure: 

 

 

Here are the steps you'll take for the upgrade: Major Upgrade of SmarterMail. As with any upgrade, please be sure to first review the 15.x System Requirements and Release Notes. In SmarterMail 15.x, the default web server is still available; however, it was removed in 16.x, so IIS would be required if you upgrade to the latest release available.

 

Finally, our office will be closed over the weekend, but we do have an Emergency Support option available as needed. 

 

I hope this helps!