Protecting your iPhone battery usage and cellular data minutes is a continual struggle. A new feature with IOS 11 provides an option for running your apps in the background. Your apps can update regularly in the background so they are up-to-date when you need them; it’s a handy feature. However, the function can consume much of your cellular minutes unnecessarily.
In the past, your option was to turn off the apps running in the background or leave them on to consume cellular data. The latest IOS update allows you to have your apps update when you are on WI-FI (not using cellular data) and not update when running away from your WI-FI connection.
Go to your iPhone Settings, select GENERAL > select Background App Refresh > select Background App Refresh again > choose WI-FI if you want to only refresh when you are on a WI-FI network. Select BACK to return (see picture).