I'm currently working on a communications product that spans a lot of on-device APIs to use them in interesting ways and in novel combinations. Part of the cha

I'm currently working on a communications product that spans a lot of on-device APIs to use them in interesting ways and in novel combinations. Part of the challenge is that complete documentation of behaviors is very difficult. Some behaviors depend on OEM and MNO choices. Some depend on drivers and hardware. They all depend on user choices for enabling various radios on a device. All of these choices can shift over time, and not just on OS updates. Even running hardware/firmware changes on a particular model can change behavior. Many of these things will appear in different combinations on new devices and different user environments. Internet APIs have fewer excuses, so challenges are more annoying in some cases. But it's always challenging to build apps that are resilient to loosely specified behavior. Such is life.