Not compatible? Update Firefox then Rated 4 out of 5 stars
I haven't tried this extension yet so can't comment on it or really rate it, but will give 4 stars since that's what the average is so far.
A couple of people, maybe more, complained that v0.7.1 of this add-on couldn't be installed because of incompatibility with Firefox 3.6.20 and 3.6.22, so they ask for the developer to correct this problem. Instead, they should update Firefox! Why always put all of the responsibility on developers to endlessly support very old versions of other software? Does Microsoft continuously supports its op. systems? Definitely not. Do Linux distribution makers? No.
If the add-on doesn't install due to Ffx version compatibility problems, then update to a more recent version of Ffx. Or download the .xpi file for installing the add-on, unpackage the file with an archiveal/unarchival app. like 7-Zip, IZarc, ..., f.e., open the .rdf file that's obtained, look for "version" and modify either the Min or Max version number, whichever evidently needs to be changed. Then save the .rdf file with this change, close the text editor, recreate the .xpi file using an archiver and giving .xpi for filename extension, and then use Firefox's Tools | Add-ons manager to install this modified .xpi file. That might not always work, but often does.
If people don't want to update Ffx due to using an OLD Windows system or other OS, or due to using OLD hardware they think is too limited for current or newer versions of software, but use Ffx 3.6.x and that works okay, then download the .xpi file and check what the Min version number is in the .rdf file. Otoh, if Ffx 3.6.x works okay, then v4 should also work fine. Install that and then this add-on might install without any problems.
People who aren't resourceful need to become that and the Web provides a lot of info. Too many people complain, instead of trying to be resourceful, first. When we've tried everything we can think of to try to resolve problems and nothing has worked, then it's time to ask questions or for help. Complaining should be the very last thing we do. Taking the resourceful route doesn't always work, but it's to be done before complaining.
The add-on is free and the .rdf file is editable, so take the resourceful approaches. And maybe the problem is something other than the .xpi provided. In that case, check the Mozilla.org and Mozillazine.org forums to see if there're answers for the experienced problems.
I regularly update Ffx and Thunderbird when notified about new releases, and a reason that I've read that this is very recommended is because many updates provide security fixes, instead of only feature or functionality differences. Security bugs need to be corrected, so I keep these apps up to date.
Mozilla indicates that this add-on is installable with my Windows system and Ffx version, and the install button is green, which means that Mozilla has fully verified this extension. So I'll install it now.