Well, that's the line that was never really discussed.
HDMI 1.4 isn't just a cable. It's an interface standard.
You will not just need new cables, but new gear which supports and takes advantage of HDMI 1.4.
If your gear is HDMI 1.1 specific, then there is no need to upgrade to HDMI 1.4 or even HDMI 1.3 at this time. You just don't get anything from it at all.
On the other hand, if you had HDMI 1.3 gear, and you had HDMI 1.1 cabling, then you may be missing out on HD audio or something else that was potentially there.
The fun of HDMI is that it likely will keep evolving for several more years until it is replaced with 'something'. Not sure what, but hopefully a wireless or CAT5/6 solution.