The firefox4-4.0-0.8.beta5 package install this new version besides the version 3.x. So you will have 2 entries in the Internet menu.

WARNING : a backup of your profile (~/.mozilla/firefox directory) seems mandatory.

Start by reading :

As always :

yum --enablerepo=remi install firefox4

No xulrunner update, this RPM provides his bundled Gecko engine.

Actually lot of extensions and themes are not compatible and will be disabled. For those I use:

  • Abblock Plus 1.2.2 : compatible
  • Add-on compatibility checker 0.6 : compatible
  • Dictionary switcher 1.0.1 : not compatible but works
  • DOM inspector 2.0.8 : compatible
  • Ecosia 1.0.5 : not compatible but works
  • Firebug 1.6X.0b1 : compatible (there's still some bugs)
  • freerecord 3.4.2 : not compatible but works
  • Personas 1.5.3 : doesn't work
  • SQLite manager 0.6.1 : doesn't work
  • Web Developer 1.1.8 : not compatible but works

Some benchmark results:

  V8 Benchmark
More is better 
SunSpider
Less is better
Mozilla/5.0 (X11; U; Linux x86_64; fr; rv:1.9.1.5) Gecko/20091105 Remi/fc12 Firefox/3.5.5   3031 ms
Mozilla/5.0 (X11; U; Linux x86_64; fr; rv:1.9.2b1) Gecko/20091106 Remi/fc12 Firefox/3.6b1   2397 ms
Mozilla/5.0 (X11; U; Linux x86_64; fr; rv:1.9.2.8) Gecko/20100724 Remi/fc13 Firefox/3.6.8 225 2029 ms
Mozilla/5.0 (X11; Linux x86_64; rv:2.0b3) Gecko/20100815 Remi/fc13 Firefox/4.0b3 812 748 ms
Mozilla/5.0 (X11; Linux x86_64; rv:2.0b4) Gecko/20100825 Remi/fc13 Firefox/4.0b4 902 537 ms
Mozilla/5.0 (X11; Linux x86_64; rv:2.0b5) Gecko/20100101 Firefox/4.0b5 Remi/fc13 909 523 ms