When I import data from my oldserver to a new server is has errors when trasfering the data.
I have update the old ubb to 7.5.5 and make a fresh install on the new server but when I use to migrate the data (i doing this whith navicat) It has error while exporting.
I'd recommend just dumping the data on serverA, transport it to ServerB, then insert it on serverB versus using Navicat or SQLYog... At least then MySQL will give you any errors versus a program suppressing them...