Rated 5 out of 5 stars

le Giant Crazy Zhu ar DFómh. 21, 2008 ·

This add on can be used in higher version of firefox and thunderbird after being made a little modification as "So, I tried to find how to tell to Thunderbird 3 to accept it. It’s in install.rdf in the xpi archive. The only thing you have to do is to seek for and then replace the 2 in the section by 3.0a2pre. So the package is there, and it works almost perfectly for me (where “almost” means “since you don’t try to run the old Thunderbird”)."

For more detail, see: http://blog.binarykatana.com/post/mozilla-thunderbird-3/