Mozilla/5.0 (X11; Linux i686; rv:2.0b10) Gecko/20100101 Firefox/4.0b10 Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.8) Gecko/20100723 Ubuntu/10.04 (lucid) Firefox/3.6.8
Works fine for me
Mozilla/5.0 (X11; Linux i686; rv:2.0b10) Gecko/20100101 Firefox/4.0b10
Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.8) Gecko/20100723 Ubuntu/10.04 (lucid) Firefox/3.6.8
Works fine for me