App slicing is not available for iOS 9 apps due to an issue affecting iCloud backups created from iOS 9. When a customer downloads your iOS 9 app, they will get the Universal version of your app, rather than the variant specific for their device type. Top iOS development companies mobile apps are keen to know all the features of iOS9 to tweak their offerings.
Just upgraded to iOS 9; will probably never use this. The four finger swipe between apps works just fine; have no need to have both apps on the screen at the same time, eating up room!
It would help apt school a lot