Rated 5 out of 5 stars

by valsaven on Dec. 13, 2017 ·

It works great on Thunderbird 52+:

1. Download the addon
2. Unzip it with 7zip (for example)
3. Open install.rdf file with your favorite text editor
4. Find the <!-- Thunderbird --> block and update the em:maxVersion section to your version
5. Zip files and change extension from .zip to .xpi
6. That's it. Drag'n'drop it to Thunderbird.