Bewertet mit 5 von 5 Sternen

The steps are:
- download the xpi file
- Launch zip
- Click open and locate file
- open the install.rdf
- locate the line which says "maxversion 1.0" (or other versions and change it to "maxversion 3.0"
- save the changes in the install.rdf zip file
- close the zip program
- install this edited file as an add-on in Thunderbird.