Apple is facing a class-action lawsuit from iPhone users claiming they were not warned the Wi-Fi assist feature in iOS 9 would use data from their cellular plan.
Plaintiffs William Scott Phillips and Suzanne Schmidt Phillips say because the of the costs associated with Wi-Fi Assist, "the overall amount in controversy" exceeds $US5 million, Apple Insider reported.
Wi-fi Assist first appeared in iOS 9, and is designed to automatically switch to cellular when a Wi-Fi connection is absent or poor.
It was switched on by default, and some users say it has resulted in large cellphone bills.
Some Android phones have a feature similar to Wi-Fi Assist, but it is turned off by default.
The complaint (see below) says Apple did not properly explain Wi-Fi Assist on its website until a "flood of articles" were written about unintended cellular data use.
Apple's support website now says: "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."
"Defendant's above corrective action, however, still downplays the possible data overcharges a user could incur," the suit said.
"Reasonable and average consumers use their iPhones for streaming of music, videos, and running various applications - all of which can use significant data.
"Defendant's corrective statement does not disclose any basis for its conclusion that an average consumer would not see much increase in cellular usage."
The Wi-Fi assist feature can be turned off by opening the Settings app and choosing Cellular, then scrolling to the bottom to find the toggle button. The option is missing on some older Apple devices.
