Apple has posted a new support document, entitled “About Wi-Fi Assist.” The webpage attempts to clarify how the new Wi-Fi Assist feature works in iOS 9. Some users claim they have seen their monthly cellular data usage grow dramatically when the feature is enabled.
With Wi-Fi Assist, you can stay connected to the Internet even if you have a poor Wi-Fi connection. For example, if you’re using Safari with a poor Wi-Fi connection and a webpage doesn’t load, Wi-Fi Assist will activate and automatically switch to cellular so that the webpage continues to load. You can use Wi-Fi Assist with most apps like Safari, Apple Music, Mail, Maps, and more.
Apple also cautions, “Because you’ll stay connected to the Internet over cellular when you have a poor Wi-Fi connection, you might use more cellular data. For most users, this should only be a small percentage higher than previous usage.”
Wi-Fi Assist is enabled by default on iOS 9 devices, and many users were surprised when they saw their cellular data usage stats had increased. Users can disable the feature by going into the Settings app, tapping the “Cellular” menu option, and then scrolling down to the “Wi-Fi Assist” toggle and tapping it to turn it the feature off.
Apple says there are certain limitations to the feature, such as it won’t switch on if data roaming is enabled, and the feature only kicks in for foreground apps, not background downloads.
