I want to check out Web Audio APi for a web page I'm building but I get a message to the effect that my browser doesn't support it. My browser is Firefox version 20 for ubuntu. I've looked at the Web Audio API compatibility table http://caniuse.com/audio-api and it says version 23, at least, is needed for the WA API. On Synaptic, the current FF is 20. How do I get a later version?

any help much appreciated.