Rated 4 out of 5 stars

I made a new file hopefully it will work. https://drive.google.com/file/d/1cHWGV5qHHr6EHAmQOpb-XSVJpkCVh1Bg/view?usp=drivesdk

This review is for a previous version of the add-on (20110323.1-typefix). 

Rated 3 out of 5 stars

This might be helpful. I have created this file for Thunderbird 52.9.1. I followed the instructions above and it works.
Download and install as a file on ad dons
https://drive.google.com/open?id=1T4CwPKMvE-vtPqoi_KP7ImFvNtMybjJc

This review is for a previous version of the add-on (20110323.1-typefix).