Rated 5 out of 5 stars

It works fine.

I started using it when it was free (and unmantained), and I intend to continue using it after Thunderbird 68 is released, so I just paid for the license.

I don't see why the new author shouldn't get a small reward for his work, since he has actually added value to the project, by adding support to TB 68 (and fixing some other small bugs).
The price is fair.

This review is for a previous version of the add-on (68.0.1). 

Thank you! :-)

Thanks to payments like yours, we can keep ExQuilla alive.