Nav 1.6.20 crashes for no apparent reason. (Have sent logs.) Route is set up with multiple waypoints. When the app is restarted, all waypoints are checked, even ones that were cleared by reaching them. One must then un-check all the ones that were already passed, otherwise the app will try to route again from the beginning of the entire route. That can be a pain, especially since the checkbox area is small. If slightly off target, the 'Select action' menu appears, which then has to be cleared and the checkbox tried again. Try doing that for multiple waypoints while riding a bicycle... also potentially dangerous while driving a car.
Best would be that the app doesn't crash. Until that happens, I suggest that the error handling could be improved. For instance, the route would be stored in non-volatile (NV) memory. As each waypoint is cleared either by reaching it or by manual clearing, the updated information would be stored in NV memory. Then if the app crashes, when it reboots the present route information with the waypoints checked/unchecked would appear. That would eliminate the need to reset passed waypoints; one could resume navigation without having to make any changes.
It also would be nice if the target area for the checkboxes could be made larger. On a Samsung Galaxy S4, the area is quite small and difficult to accurately hit when in motion (for example, on the above-mentioned bicycle).
Have been using the beta version for a while. The version seems to be more stable, with far fewer crashes. However, I have experienced some crashes with having un-check all passed waypoints upon restart. When we go for a bike ride, we often have many waypoints in the route to keep us off of busy roads. So clearing waypoints on a reboot can get aggravating. So I still recommend the NV memory feature I described in the second paragraph above.