Is it necessary to check the value of $_GET['is_app_user'] in an iframe application?

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Hello, I have developed an HTML5/Websockets game for PC and Android and am currently trying to launch it on various platforms, incl. and on VKontakte.
Unfortunately, while I'm getting a refusal and the support service claims that my game is not visible at all (although I can see it from my wife's account):

In the PHP script of my application it is at the very beginning (I removed this block right now, since I sent the application again For checking):

if ($_GET['is_app_user'] != 1) {
        exit('App is not installed');
}

My question is: is this check needed at all or is it outdated (I adopted it from another, old script) and the application will work anyway?
And is it recommended to mark "Application installation: not required" in the application settings?

Answer 1

The application will work.
If you need functionality. for the user to install it - make a softer handler, that is, for example, a notification that you need to install the application without cutting off the functionality.