Apple’s new iOS 9 has some new features which are really useful and also a lot of improvements when it comes to stability and bugs quashing, but unfortunately, one of them may be killing your data plan without you knowing it. iOS 9’s new WiFi Assist feature will automatically switch to your mobile network for data if you’re experiencing a bad WiFi connection…For example, if you’re using Safari with a poor Wi-Fi connection and a webpage doesn’t load, Wi-Fi Assist will activate and automatically switch to cellular so that the webpage continues to load.
Though, Wi-Fi Assist will not automatically switch to cellular if you’re data roaming. Wi-Fi Assist only works when you have apps running in the foreground and doesn’t activate with background downloading of content.
Unfortunately, since there’s no prompt for this switch, there’s a chance that your data plan is being depleted even while you’re doing nothing in a WiFi zone. Since this WiFi Assist is on by default, you should really consider turning this off completely.
To do so, simply head to Settings>Cellular and turn off WiFi Assist all the way at the bottom.
