IIP shouldn't have affected your forums in that manor. I upgraded from 5.2 to 5.3 here at threadsdev in a few minutes with no problems. What version did you upgrade from? Did you run the modify database script? What did it say?
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.
