Rated 5 out of 5 stars

This is awesome. Thanks for porting XNote++.
I installed 0.4 and tried importing my old notes and they don't show up.
I tried with the "Inside extension" setting and by using the "Local folder".
When set to "Inside extensions" and clicking on the "Import legacy XNotes" button, I get the following report:
Import finished:
imported notes - 0
errored notes - 0
existing notes - 12
Why is the imported notes set to 0?
Once the import works, this will be a 5 star.
Thanks for your efforts!

Update: The import works properly. I was looking in the wrong folder for the notes! 5 stars!!

This review is for a previous version of the add-on (0.4). 

"existing notes - 12" means 12 notes has been already imported before. You can do export storage and open it in any .json reader to see contents.

Do you have checkbox checked to open notes automatically? If not then QNote button should light up in message pane.