I just checked my tablet which hasn't upgraded and you are right. There was a menu bar at the bottom. It had different icons but I think, because there isn't a dark line at the top of the menu bar to separate it from the list of emails, it looks a bit odd. I've set my main colour to a light grey similar to before but it seems to lack definition. I don't want to use a dark colour as I find it more distracting but would like to see a dividing line when an upgrade is due.