xenforo app

One of my users stated that he got a white screen on his forum app since recently. He already used the app, but now if he clicks on it, he gets a white screen. Without the app, forum is working perfectly. In the admin section, nothing changed and all is green stating "Your board meets the...

I need a xenforo's coder, able also with app development, to build a native app for iOS and Android. The app should support all xenforo's plugin and also i should maintain the source of app. In private, more details.