Latest Firefox 4 user agents:

User Agent Platform Device
Opera/4.0 (Macintosh 3.1; rv:2.0.1) Gecko/20100101 Firefox/4.2.1 Mac Unknown
Opera/4.0 (Macintosh 3.0; rv:2.0.1) Gecko/20100101 Firefox/4.0.3 Mac Unknown
Opera/3.0 (X11; Linux x86_64 4.0; rv:2.0.1) Gecko/20100101 Firefox/4.3.3 GNU/Linux Unknown
Opera/3.0 (X11; Linux x86_64 3.1; rv:2.0.1) Gecko/20100101 Firefox/4.0.1 GNU/Linux Unknown
Opera/3.0 (X11; Linux x86_64 3.0; rv:2.0.1) Gecko/20100101 Firefox/4.0.1 GNU/Linux Unknown
Opera/3.0 (Macintosh 4.1; rv:2.0.1) Gecko/20100101 Firefox/4.0.1 Mac Unknown
Opera/3.0 (Macintosh 3.0; rv:2.0.1) Gecko/20100101 Firefox/4.4.1 Mac Unknown
Mozilla/5.0 (X11; U; Linux i686; en-GB; rv:2.0) Gecko/20110404 Fedora/16-dev Firefox/4.0 Fedora 16 Unknown
Mozilla/5.0 (X11; Linux; rv:2.0.1) Gecko/20100101 Firefox/4.2.33re GNU/Linux Unknown
Mozilla/5.0 (X11; Linux x86_64; rv:2.2a1pre) Gecko/20110324 Firefox/4.2a1pre GNU/Linux Unknown
Mozilla/5.0 (X11; Linux x86_64; en; rv:2.0) Gecko/20100101 Firefox/4.0 GNU/Linux Unknown
Mozilla/5.0 (X11; FreeBSD amd64; rv:2.0.1) Gecko/20100101 Firefox/4.0.1 FreeBSD Unknown
Mozilla/5.0 (Windows; Windows NT 6.2; WOW64; rv:2.0b3) Gecko/20100805 Firefox/4.0b3 Windows 8 Unknown
Mozilla/5.0 (Windows; Windows NT 6.1; WOW64; rv:2.0b3pre) Gecko/20100728 Minefield/4.0b3pre Windows 7 Unknown
Mozilla/5.0 (Windows; Windows NT 6.1; WOW64; rv:2.0b3) Gecko/20100805 Firefox/4.0b3 Windows 7 Unknown
Mozilla/5.0 (Windows; Windows NT 6.1; WOW64; rv:2.0b3) Gecko/20100805 AskTbFXTV5/3.8.0.12304 Firefox/4.0b3 Windows 7 Unknown
Mozilla/5.0 (Windows; Windows NT 6.1; WOW64; rv:2.0b2) Gecko/20100720 Firefox/4.0b2 Windows 7 Unknown
Mozilla/5.0 (Windows; Windows NT 6.1; rv:2.0b2) Gecko/20100720 Firefox/4.0b2 Windows 7 Unknown
Mozilla/5.0 (Windows; Windows NT 6.1; ru; rv:2.0b2pre) Gecko/20100719 Minefield/4.0b2pre Windows 7 Unknown
Mozilla/5.0 (Windows; Windows NT 6.1; en-US; rv:2.0b2pre) Gecko/20100718 Minefield/4.0b2pre Windows 7 Unknown