Hi Bruce
The issue is not about an AR 9.0A upgrade, it is about an IN 8.1B upgrade. I think you might have misread the thread.
I am not sure whether IN 8.1B performs a data conversion, if it does then you will have to restore from a backup. If it doesn't, then simply re-installing 8.1A should work.
But what does tech support have to say?
Steve