Watching the ThermalState of iPhone and notify the user [closed]
This app does not seem to fit in any of the categories deemed okay to run in the background at all times. Getting it into the App Store would be quite difficult, I imagine.
I also do not see why any user would want this program. You have included no justification for it in the question. Basically, if the thermal state is critical, iOS already has existing functionality to warn the user directly letting him know the device needs to cool off, so you wouldn't need a third party app to do the same thing.