Mozilla says the next major version of Firefox will drop support for Mac OS X and require Mac OS X 10.5 or 10.6.
“We believe a Mac OS X 10.5 minimum will allow us to provide the best experience possible to our users,” Mozilla Mac programmer Josh Aas said in a mailing list announcement (http://groups.google.com/group/mozilla.dev.planning/browse_thread/thread/4e1b9692c202c40a). “This does not affect current users of Firefox, or updates to Firefox 3.6: Mac OS X 10.4 will continue to be supported via Firefox 3.6 until its end-of-life (not yet scheduled).”