Android P DP4 just debuted earlier today, and even on the fourth developer preview, Google is still adding new changes. We'd thought that the only new things we'd be seeing by now were stability and bug fixes, but apparently not. The gesture navigation introduced back in May has received a new back button in DP4.

left: DP3. right: DP4.

Both of the gesture navigation's buttons have been revised. The back button is no longer a triangle, and it's slightly shrunken in size. The home/recents button is now darker as well. To my eye, these changes have improved the overall look, making the gesture navigation look less like an experiment and more like a legitimate feature. Unfortunately, the concept of gesture nav without getting rid of the nav bar itself still doesn't make much sense.

We're still digging up the new aspects of DP4. It looks like there are quite a few UI changes, so stay tuned.