The release of iOS 7 added a new background service called background fetch, which allows an app to poll for new data, updates, or changes at regular intervals. For example, a weather app can update itself during the day, or a news app can fetch new articles throughout the day.
The interval for background fetch can be set. However, this is not recommended as setting an interval that is too short will cause iOS to ignore it in order to save battery life. So, in this example, we will be using Apple's default settings. Typically, background fetch runs by default, in the morning, evening, and periodically in between.
Background fetch will also run a few minutes after a device is restarted, due to any of ...