Can't open old Notebook after upgrading to One Note 365

I upgraded from Microsoft 10 to 365 and upon opening One Note I couldn't find one of my notebooks.  After many hours and much searching and googling I found a back up in: Users - My account - Microsoft - OneNote - 15.0 - Backup

BUT.... It will not let me open it.  It just comes up with a message saying you have a newer version of office installed and then says you need to uninstall this to install older versions.

I have other Notebooks that I can open fine.  How do I get this to work in One Note or at least open it so I can copy and paste the pages.

BEYOND FRUSTRATED AND ANNOYED.