Rated 5 out of 5 stars

by xecutable on Sept. 6, 2017 · permalink

Click on the Download Anyway button. Get the file. Open the file with your favorite Zip program. Edit the file install.rdf. Find the Thunderbird maxVersion: 38 and change it to a number higher than the current version.

For example I changed it to 58. Update the archive. Go to your addons tab, and click on the wheel and select install Addon from a file. Done. The installation starts and works.