I managed to snag a couple of these before the sold out and got them paired today. Unlike the previous model, this one includes generic power button and a new hue scene controller button.
As far as behavior goes, using the built-in Philips Dimmer Button Controller driver, the generic power button cycles between a button 1 and button 4 push, the middle two buttons still support pushes and holds, and unfortunately the driver doesn't recognize whatever is happening on the hue scene controller button.
Really excited to integrate these into my bedside lamps as being able to toggle my night and morning scenes from my bed without using a dashboard is very appealing. Just need a driver update.