We had a user recently who had gone over their data allowance and incurred additional charges. ‘But that’s not possible,’ he said. ‘I hardly ever use data when I’m not connected to wi-fi, so how can I go over my limit?’

With the advent of Wi-Fi Assist in iPhones, the answer to that is: easier than you might think!

Apple are always keen to introduce ways of improving a user’s mobile experience, and clearly a poor wi-fi connection can be irritating – especially when streaming music or video. So from iOS 9 they introduced Wi-Fi Assist which does what it says on the tin – it assists you when your wi-fi connection is poor. How? By automatically switching to your 4G connection and using some of your data allowance.

In most cases this won’t be an issue, but if you are consistently connecting to a poor wi-fi network (perhaps you’re in the far corner of an upstairs office!) then you could be regularly using up data, even though the wi-fi symbol is showing that you’re connected to a network. Understandably, you’d assume that were not using any mobile data at all, but you’d be wrong.

If you think it might be a problem for you, you can turn off Wi-Fi Assist by going to Settings > Mobile Data. Then scroll down to the bottom and tap the slider for Wi-Fi Assist.