What is the last Firefox version that works with MAC Lion OS X 10.7.5? I have a study program of that vintage that plugs into firefox and the version on the computer now is 3.0.10 (from year 2009 and the program does not work with it. The program is compatible with Lion OS X 10.7.5 but the Firefox version is too old. The version 3.0.10 on the computer does not work well with most sites or crashes. The intent is not to expect to browse, just be new enough for this program for its dedicated use.