Trying to do screen capture with private framework

Question

I'm working on an existing (non app-store) app for a client that uses the IOSurface private framework to do screen captures while in the background. There are a few threads here on SO that outline the technique, as well as several open source example projects.

Again, this is an internal application used by the client. It isn't intended for app-store release, so the fact that it uses private frameworks is acceptable.

Here is an example project on Github that uses a very similar technique:

https://github.com/k06a/UIView-FastScreenshot

I just tried to run the client's app on the latest iOS 9 beta, and it crashes with the error that it is unable to load the library CoreSurface.

I've seen documentation that CoreSurface is the previous name of the framework that became IOSurface, but it also seems that in iOS 8 there is indeed a private framework called CoreSurface as well as a private framework called IOSurface.

Has anybody else been able to use IOSurface to do screen captures from the background in iOS 9?

I'm adding a bounty for anybody who can give me a way to make this work for iOS 9 (again, private frameworks are fine, but it can't be on a Jailbroken device)