Well like I said I do not have a copy of UBB v6.5 or anything past v6.1.0.4 for that matter.
You can try to install it and let us all know if it works. OR I will do the install for free on your site just so I can confirm it does or make the necessary changes so it will.
Donate to UBBDev today to help aid in Operational, Server and Script Maintenance, and Development costs.
Please also see our parent organization VNC Web Services if you're in the need of a new UBB.threads Install or Upgrade, Site/Server Migrations, or Security and Coding Services.