A new feature in Apple's iOS 9 meant to help users get better performance can have serious consequences for users with limited data plans.
Wi-Fi Assist lets the iPhone switch to regular cellular data service when the Wi-Fi connection is poor.
Sounds good, right?
But it can be a disaster if you have a limited data plan and the phone switches over to cellular data during heavy streaming like watching a Netflix movie or listening to steaming music like Apple Music or Pandora.
The phone does not warn users when the phone makes the switch.
Users can disable the feature by going to "Settings", "Cellular" and then scroll down to "Wi-Fi Assist" to toggle it on or off.
Turn the feature off if you don't want to have a nasty data charge on your phone bill.