Directory location for Message+ backup on SD Card

I'm helping my wife migrate from a 5+ year old Motorola Droid to a new Moto G Stylus, and she has years of old txt messages in Message+ that she wants to keep.  I've managed to create the back of them on the old phone, but it was only made on the internal memory, not the SD Card.  I've transferred everything to the SD card of the new phone, but Message+ doesn't see the backup in order to restore it.  I just need to know the directory location that Message+ looks in for backups to restore.