Have you already updated your iPhone to iOS9? If you have, you might have discovered that Apple introduced a new feature in its latest operating system update. It's called Wi-Fi Assist, and while it ensures connectivity to the internet all the time, it could end up costing you a lot on your cellphone bill.

In its default setting, the Wi-Fi Assist is set to be on at all times, according to Time. What this does is switch to your iPhone's cellular data when it senses a weak Wi-Fi signal. This boosts your phone's access and connection no doubt, but it will definitely eat up your data plan. If you're not subscribed to unlimited data, you'll end up going over the maximum rather quickly, and your mobile phone bill will be sky high.

Users on Twitter have reported going over their data cap from one to seven GB because of Wi-Fi Assist.

Here's how you can deactivate the feature to save data on your iPhone and save your money.

1. Under "Settings" open the "Cellular" menu

2. Scroll down to the bottom of the page and you will see "Wi-Fi Assist"

3. Turn it off.

It's a fairly simple solution and it's not a bug or glitch from Apple, according to Quartz. Once switched off, you can use your iPhone's internet connectivity to your heart's content again, regardless of the slow connection.