I need to download Firefox 4 because that is the only version (so far) that is compatible with my banks website. How can I find this download on Firefox website? /Lars

I had Firefox 4 installed and working until to day when I had problems login to my bank website. After contact with bank support I was recomended to change version to 3.6 on Firefox. I did so but the problem concisted and after a new support contact the problem was solved but I now was told that version 4 was ok to use (but not version 5 yet). I have now tried to find version 4 on Mozilla Firefox website but without succeding. How can I find and download Firefox 4? /Lars