I'm using C# (Xamarin) on iOS, but I suspect this question applies to those programming in Objective C as well. iOS 7 introduces the background "fetch" functionality which lets the app download data while it is in the background.
All of the docs I've read (on both Xamarin's and Apple's sites) state that this functionality is for downloading updates, and that you have around 30 seconds to finish the download; however, nowhere are restrictions stated. I'm wondering if it's acceptable for my app to also upload things to our servers when in the background.