The actual practice in software houses is to certify their software against a limited number of browser versions. Otherwise, the testing costs would be too high

The actual practice in software houses is to certify their software against a limited number of browser versions. Otherwise, the testing costs would be too high. In addition, software couldn't be tested against unreleased versions, so no matter what, the certified environments would always be out of date. This is not a problem as long as security issues have been addressed. You will not find any vendor who promises you that their software will work against the next version of Firefox. So, as the I.T. head, you need to make cautious choices so that the technology mix will in fact work.