I have to agree that this is a good time for some house cleaning.
When migrating from Windows based VM (assuming this is what you have in place now), we always backup/restore to the same release then do an in place upgrade on the new machine. I have tried backing up a Windows based deployment on a lower release and moving directly to a higher Linux release and it never works. This is a little tougher since Server Edition didn't exist in R7 for your situation.
My theory-craft here says you would have to spin up an application server on R7, restore the backup to it, upgrade it to 9.1, pull a backup from it, and import into the SE. I may be overthinking that one a bit but it sounds like the most solid way to make sure all greetings, names, etc all stayed active.
Or do as IPGuru said, and pitch is as a good time for house cleaning. (recommended)