Apple's iOS 9 has brought with it some great new features for iPhone – but one new feature may prove costly for users who have a limited amount of mobile data to play with each month.
Wi-Fi Assist, which uses your mobile data if a wireless internet signal that you're trying to use is proving weak, is enabled by default in iOS 9, which means it could start eating into your monthly data allowance.
If you do have a limited data package, we'd recommend turning Wi-Fi Assist off now before it racks up an enormous and unexpeted bill.
How to do it
To do so, you'll need to head into the Settings app on your iPhone and tap on Mobile Data (or Cellular if you're in the US). At the bottom of the page is a toggle for Wi-Fi Assist, so you just need to switch this off.
This tip first appeared as one of our iPhone 6S tips and tricks – for more tips that will help you get the best out of Apple's latest handsets, check out the video below.