latest iphones won't rotate upside down

I came here because i was trying to find out how i can rotate my phone upside down, just like the original poster, i charge my phone and leave in the cup holder to see my google maps and with my 6s i was able to flip it and charge and see the map the right way but now it won't flip upside down so that is very unfortunate to lose such good features when we upgrade our phones. Apple please fix this