ios - What's difference between NSPhotoLibraryAddUsageDescription and NSPhotoLibraryUsageDescription?

Question

My app get crashed today while updating on Xcode9, testing on iOS11. After adding NSPhotoLibraryAddUsageDescription then it works, even i already had NSPhotoLibraryUsageDescription.

Ive read about them, one supported since iOS6, one iOS11 but Apple didn't mention what's difference between them. https://developer.apple.com/library/content/documentation/General/Reference/InfoPlistKeyReference/Articles/CocoaKeys.html#//apple_ref/doc/uid/TP40009251-SW73

If i keep the new one (NSPhotoLibraryAddUsageDescription), will it work for iOS 8 also or i have to keep both of them?

Answer 1

Simple get from Apple Official Document

Just click on above image for ZOOM and read it.

For more information on:

• NSPhotoLibraryAddUsageDescription: If you want to save a photo/image to your Photo Library. For iOS11 and +

• NSPhotoLibraryUsageDescription: If you want to access your Photo Library. For iOS10 and +