Not much Kentico has to do with that, but from what I can find the only option you have is redirecting to app specific link. If that doesn't work you either don't have the app or don't allow the url to be opened by the app.
https://stackoverflow.com/questions/13044805/how-can-i-check-if-an-app-is-installed-from-a-web-page-on-an-iphone