RPM of the new major version of Mozilla Foundation browser is available in remi repository for Fedora. This version provides 73 langs.
Start by reading :
As always :
yum --enablerepo=remi update firefox
No xulrunner update, this RPM provides his bundled Gecko engine.
Most of extensions are now compatibles and works as expected.
About Java plugin, version provided by OpenJDK is not compatible (OJI support dropped), so you must switch (back) to the Sun Java and use the new extension (NPAPI). Quick notes (need to be changed according to version and architecture used):
rpm -e java-1.6.0-openjdk-plugin
rpm -ivh jre-6u17-linux-amd64.rpm
ln -s /usr/java/jre1.6.0_17/lib/amd64/libnpjp2.so /usr/lib64/mozilla/plugins/
RPM are available for Fedora ≥ 8.