IMPORTANT: To ensure reliable track logging when your phone screen is off: (1) Allow Handy GPS to always use GPS (Settings > Apps > Handy GPS > Permissions > Location > Allow all the time); (2) Turn off battery optimisation for the app (Settings > Apps > Handy GPS > App battery usage > Unrestricted); and (3) Make sure battery saver mode is not turned on for your phone (Settings > Battery > Battery Saver > off)