Keep XMM 7 at the moment an install XMM 8 in another directory beside of it. XMM8 will transform a copy of your database in the new format. That you will find in C:\ProgramData\Binaryworks\XMM8\Databases. You can later take it from there and move it somewhere else and point XMM to the new location. I would keep XMM7 and the old Database as a backup(even backup the old database before installation). This way you can test XMM8. Depending on your need it is still a work in progress. Read some of the treads here and try it.