Cannot answer calls on iPhone (iOS) devices, when locked

Although Location Services is an optional setting, iOS is enforcing the option when the device is locked.
We acknowledge this is a bug, and our developers are working with Apple to correct the issue.

In the meantime, there is a work-around:

In the iPhone (iOS) device settings...
  • Select Privacy Settings 
    • Location 
    • then Real Softphone app
  • Set Allow Location Access to Always

Your device will now allow calls to be answered, from a locked screen.