(ECNS) -- Two Americans have filed a class-action lawsuit against Apple over its Wi-Fi Assist feature in the iOS 9 system, which may secretly chew up users' cellular data and cause overcharge fees, according to media reports.
The new setting, which is on by default, allows iPhones to automatically switch to cellular data in the event of poor Wi-Fi connections.
Unaware of the new feature, many users reported a drastic surge in data usage after upgrading their cellphones to the iOS 9 system.
The Florida-based plaintiffs, William Scott Phillips and Suzanne Schmidt Phillips, argue that Apple failed to adequately warn users of the looming consequences.
They're demanding that Apple should reimburse customers for overcharges, which reportedly could top $5 million.
Apple has explained that the switch of connection will only take place when the Wi-Fi signal is extremely weak, and that the feature won't function when roaming.
Some analysts say it's more appropriate if customers can choose to use the feature.
