Heads up Apple iOS users. One feature in the recently released iOS9 update has the potential to bite users on fixed data plans. The new ‘Wi Fi Assist’ feature doesn’t do anything to make it’s presence known, but the feature defaults to an ‘on’ state in the iPhone 6S and in earlier iPhones that have upgraded to the latest OS.
Wi-Fi Assist works by supporting the phone’s data connection in weak wi-fi coverage areas by augmenting the signal with mobile data. This can make data usage unpredictable for users on fixed data plans. Some users have found mobile data usage to have doubled or tripled since the update.
If you’re uncertain about your devices settings and have a fixed data plan, find Wi-Fi Assist and toggle it off to be safe.