How to Make It Work: Editing an Add-On's Compatibility Rated 5 out of 5 stars
As previously mentioned, this article tells you how to edit an add-on's max version.
It's a lot easier than it looks; takes about 30-60 seconds.
1. Download the aarvark add-on
2. Open it with 7-zip (free) or another archiver
3. Extract "install.rdf" and open it in notepad
4. Look for <em:maxVersion> and change the version number to whatever you want.
5. Save and replace it back in the archive
6. Install it in firefox
Almost easier than using Aardvark itself!
Works with any add-on / extension too.