One of the multitasking features introduced with iOS 7 was background fetches. Selene is an open source library from the LinkedIn engineering team providing a very easy way to scheduling background fetches.

Selene automatically determines which background fetches to execute based on the priority, average response time, and elapsed time since last execution, with a 30 second timeout for tasks. This way only the most important tasks are executed preserving performance, bandwidth, and battery.

You can find Selene on Github here.

You can read more about Selene on the LinkedIn engineering blog.