Attention From now, The firefox-4.0.1-1 package replace the standard version (3.6.x).

Start by reading :

As always :

yum --enablerepo=remi update firefox
This RPM use the Gecko engine provided by xulrunner2 (which could be installed beside the default system xulrunner).

The Add-on compatibility reporter 0.8.3 allow to enable extension which are not compatible for test.

RPM are available for fedora >= 10.