View size change in iOS-9.

Hi everyone,
I have an iOS application and when the OS is updated to iOS-9 the size of iPhone 4s. The problem seems to come from the AppIcon class. If I remove it it works ok, however the App loses its icon on the device (makes sense). The app works portrait on iPhone 5 (and iPod with the same screen size) as well as landscape on the iPAD.
Up to iOS 8.4 it works in the proper sizes in iPhone 5 and iPhone 6.
The same on the simulator (in iOS 8.4 it appears Ok but not on iOS 9, 9.01).

Any ideas?

Are all your Launch Images set correctly? They make a difference on iPhone 5+.

Hi Ian. I think they were set correctly, however I will check them again.
The thing is that up to iOS 8.4 everything worked correctly.
And if I delete the AppIcon class then it works Ok again, just with no icon for the application!
I recreated the AppIcon directly, putting in it the appropriate images, but I got still the same problem.

Unfortunately removing and putting again the Launch Images is not it! I might be missing something very simple, however, it is quite a serious problem.