What to back up
Everything the hub holds is in your WordPress database — tickets, replies, customers, licences, usage — plus the files under uploads/keen2support/, which hold the attachments and, unless you have moved them, the release ZIPs.
If the package folder has been pointed somewhere above the web root, back that folder up too — it will not be inside the uploads directory.
A database-only backup restores your tickets but not the files attached to them.