IOMobileFramebufferGetLayerDefaultSurface not working on iOS 9

Question

My main question is, how can I reverse engineer a private API function that already exists, but has been modified in a new version of iOS?

I have created an iOS app

Answer 1

IOMobileFramebuffer is completely locked down on iOS 9 and cannot be used from non-Apple apps anymore. AFAICT, this closes the last private API to capture the screen efficiently. ReplayKit is the only replacement, but does not allow programmatic access to the actual video data.