4 Turn Off Background App Refresh
Background App Refresh, in the simplest terms possible, is a feature that lets apps check for new content the background so that it’s ready for viewing when the app is launched next. It can also unnecessarily drain battery and data if you’re not careful.
There are some other concerns about the feature, too. Such as whether or not it’s actually critical for apps to remain updated (honestly, the answer to that is usually no). Also, there’s the matter of whether or not you actually trust the app developer in question to not abuse the feature. If the answer to either of those is no, then go to Settings > General > Background App Refresh.