If you don’t have an unlimited data plan with your iPhone or iPad, and have updated to iOS 9, there’s a feature buried in the Settings that may be eating through your monthly data cap.
A little-discussed feature in iOS 9, called WiFi Assist, was designed by Apple to help improve slow wireless connections by allowing the phone to utilize cellular data to enable users to finish loading, say, that cute cat video your Aunt posted to your Facebook wall.
Problem is, your iOS device doesn’t notify you when it switches from WiFi to cellular unless the WiFi connection is dropped entirely. Therefore, many users are unknowingly burning through their limited data plans when, in fact, they believe they are connected to a WiFi network.
WiFi Assist has been enabled by default in iOS 9 — and, it’s not all that easy to find, either.
Buried at the bottom of the Cellular tab in Settings is the toggle for WiFi Assist. Disabling this feature will prompt your phone not to resort to relying on cellular data on slow WiFi; which, may slow down those cat videos, but certainly won’t chew through your limited data cap or result in surprising monthly bills, either.
While the “iOS 9 Data Monster” is a bit unsettling — given there wasn’t much, if any, notification by Apple — it’s unlikely the result of anything nefarious by the company.