Well it is the latest official final release version, but Mozilla have released a later "Beta Version": . Firefox 5.0 Beta 1 . It can be downloaded from http://funadvice.com/r/1530b8u0uph . I have not tested it myself so I cannot recommend it, and as with all Beta versions, it is better not to use it on your main machine unless you are willing to risk a major problem due to bugs that still have to be found and fixed during testing.
Best wishes - Majikthise. .
No it is not thats pretty old I think it might be 8.o.1