Update of Android system to P version probably will offer much more than only improvements in topic of system performance. People said that design of system will change dramatically, but when it comes to visual changes we shouldn't receive many modifications, but one change may be breakthrough because on screenshots of updated system we noticed some improvements on navigation bar.

All the signs point to removing multitasking home button from center of navigation bar. This change may results from adding gesture navigation to Android P, and even icon which will replace standard circle points to such a reason. We received information that both buttons from navigation bar (back button and new button connected with gestures) won't appear on our screen when we won't have option to use them - so, for example, back button won't appear on home screen.

source