... Have Arturia changed the plugin name or descriptor with this update? If so, what's the workaround? ...
Actually they did rename the Mg Modular V 2 and the MiniMg V! The new name is
Modular V 2/Mini V .dll or .vst3 and you can:
a) rename the plugin-file to work with your tamplates and projects, or
b) save your templates and projects with the new plugin.
(Same for the EFX version.)
There are no path changes under Windows!
To work with the Laboratory Software again, you have to update the Laboratory to 1.5.1.
PS: The Factory doesn't need the plugins or virtual instruments at all, it's independent. I guess you where talking about the Laboratory...