If all you want is a stand alone iPhone App to pair with your DuoTrap / DuoTrapS, Wahoo works great! Just add in the DuoTrap as “Other Wahoo Sensor”. It might show an error of N/A RPM & N/A Cadence but when you go to Record mode it works just fine showing current speed & cadence, tracking map, etc (don’t forget to set tire size)