The first I was aware of this "new" protected area was when I recently noticed the number 3.7 instead of 2.3 nm in our manuals. Since I had not heard of this before, and there were no relevant notices to crew or any other such communication, I started looking online and couldn't find any FAA reference either. Thus I turned to you esteemed gentlemen!
Next step, ask Line Ops what they're on about...