by Ken Task.
A plugin/addon that was compat with 3.11 and used in a course but not compat with 4.5 would create problems.
I really don't know of a way to preview that in the GUI if all you have is the .mbz file ... only by extracting the .mbz file in a test directory and then inspecting the xml files with associated directories ... activities and modules ... one might discover one. :|
If discovered, on importing course one would step through and then not include those activities/mods in the restore.
'SoS', Ken