JKD is constantly evolving and must always do so, if it's to live in accordance with it's principles.
Of course that depends also with whom a person is studying. Some folks don't agree that it should evolve at all. Those people paint JKD as a "style" that should be rigid and "fixed" (the fixed pattern that Bruce Lee so abhorred). Naturally I think this goes against JKD's very principles.
So the short answer is yes, it's definitely changing.