If youre looking for Khmer system keyboard for iOS8
Please check Black Keys app from us
http://itunes.apple.com/app/id899894778
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This keyboard help you install font, type in Khmer and quick copy to your App.
*NOTE:
-install font in iOS7.1: open all apps you need to copy text(Facebook, email, SMS...) , dont close them and open Khmer Keys to install font(hide keyboard - setting icon - install font)
-iOS7.0: just install font and restart all apps