Good afternoon Douglas,
Thanks for the inquiry about moving SmarterMail to a new server and performing an upgrade in the same process. Please keep in mind that due to the file structure changes from SmarterMail 7.x and above we do recommend installing this build prior to implementing SmarterMail 13x.
We do have a few articles on how to perform the steps and you may be familiar with the server requirements and specifications. Please note that you may want to configure the server first in preparation of the move. Please install any updates and server specifications, such as .NET 4x and any IIS components.
I would suggest to try and implement at least the current build of SmarterMail 7.x on the old server to ensure that the folder structure changes takes place and then when you have the data backed up and you are ready to move to the new server you can either install version 7x and confirm that it is working properly and then install the current build of SmarterMail 13x.
Please let us know if you have any other questions and open a Support ticket.
Thank You.