If you're looking for Khmer system keyboard for iOS8
Please check Black Keys app from us
This keyboard help you install font, type in Khmer and quick copy to your App.
-install font in iOS7.1: open all apps you need to copy text(Facebook, email, SMS...) , don't close them and open Khmer Keys to install font(hide keyboard - setting icon - install font)
-iOS7.0: just install font and restart all apps