The web has practically been clogged this week with posts providing tips about Apple's new iOS 9 mobile operating system: Good thing Apple added Wi-Fi Assist to make sure you're on the best connection possible to read all that stuff. Or maybe not.
Many, including those in one university IT department and at least one carrier (Vodafone), have warned about the possibility that Wi-Fi Assist could jack up your data usage if it keeps kicking you over to 3G or 4G cellular when you're in a weak Wi-Fi area. The feature is turned on by default in iOS 9.
Here's the alert issued by McGill University's IT group:
iOS 9 mobile users: consider disabling the Wi-Fi Assist feature
If your iPhone or iPad is running iOS 9, you may want to disable a new feature called Wi-Fi Assist. If you're somewhere where your Wi-Fi signal is deemed to be too slow or unreliable, it will switch to use your data connection.
The feature is meant to give you a more seamless experience when on spotty Wi-Fi networks, but this also means eating through your 500mb data cap without knowing it. You might think you’re safely Youtubing while on Wi-Fi, but instead it's using the 3G / LTE.
I floated this by a broader group of university IT professionals, to ask if others were issuing similar warnings, and got this response from one: "I believe that this is a slippery slope where the community will assume we're aware of any/all shortcomings in the IoT universe. If I send out a report about the Wi-Fi Assist feature in the iPhone, but don't send a warning about <insert device here>, it will be my fault..."
Other concerns about WiFi Assist are that it can muck up performance of online games, as discussed on social aggregation sites such as Reddit. Others on Reddit warned about WiFi Assist burning those without unlimited data plans, but still others pledged their support for the feature, which they said keeps Spotify, games and other apps humming as they move about.
Among others throwing their support behind Wi-Fi Assist is The Guardian, which posted an article headlined: "Ignore the haters: Wi-Fi Assist is the best new feature in iOS 9," rejecting the warnings issued by those such as Gizmodo's Chris Mills about Wi-Fi Assist eating his cellphone data.
One defense of Wi-Fi Assist is that it's not so much this feature which can blow up your data usage, but rather, a lack of attention to which of your apps are given permission to use cellular data. That access can be revoked on the same Settings screen where you access Wi-Fi Assist. (There's been some discussion of this in Apple Support Communities.)
And speaking of that, here is how you access Wi-Fi Assist. Go to Settings<General<Cellular and then scroll all the way to the bottom of the screen. Not real obvious, but there it is.