Our test environment was updated to FF 10 before the last release, and we have positive feedback from 11 and 12. I had heard that there were problems with 13. You could put an enhancement in for the FF 13 / 14 support. As far as I'm aware this would involve updating our selenium version and making sure that none of our current actions / support has any problems with the new version.
I am not quite sure why I would have to enter a "improvmenent"-request for new firefox-releases. Shouldn't it be in your own interest to be able to test with the latest (including possible security fixes) version of Firefox?