Rated 5 out of 5 stars

Installed beta import-export-tools-ng-14.0.0-b8 and it worked fine for what I needed (folder & message exports). I haven't yet tried MBOX import.

This review is for a previous version of the add-on (12.0.4). 

njh
Thanks for the report and review!
If you run into anything please post on Github.
Cheers
Christopher