If you ever use your iPhone on poor-quality WiFi networks, you may want to check your mobile data usage. As Quartz noted, a new feature introduced with iOS 9 is leading some people to see dramatic increases in their mobile data usage.
Wi-Fi Assist means that iOS recognizes slow WiFi and supplements it with mobile data. Great for ensuring your browsing experience doesn’t suffer, but it can come at a cost, with some users reporting that their iPhone is now using literally gigabytes more mobile data since upgrading. Unless you have unlimited data, that can get expensive.
Wi-Fi Assist is on by default, and rather hidden away in Settings, so here’s how to switch it off …
You can switch it off in Settings > Mobile Data – but you could be forgiven for not noticing it, because unlike other system-wide toggles which appear at the top of the screen, Wi-Fi Assist is tucked away at the bottom, underneath all the app-specific toggles.
This settings screen is also where you can check out your mobile data usage.
Apple reported a week ago that iOS 9 has experienced the fastest adoption rate of any version of its mobile operating system. If you still haven’t had time to explore it fully, check out our walk-through of the new features.
Via Business Insider