How to use ARCore Session.CheckApkAvailability (); ?

Try this: (Tested on Samsung Galaxy S7 Edge)

    private IEnumerator CheckCompatibility()
 {
     AsyncTask<ApkAvailabilityStatus> checkTask = Session.CheckApkAvailability();
     CustomYieldInstruction customYield = checkTask.WaitForCompletion();
     yield return customYield;

     ApkAvailabilityStatus result = checkTask.Result;

     switch (result)
     {
         case ApkAvailabilityStatus.SupportedApkTooOld:
             _ShowAndroidToastMessage("Supported apk too old");
             break;
         case ApkAvailabilityStatus.SupportedInstalled:
             _ShowAndroidToastMessage("Supported and installed");
             break;
         case ApkAvailabilityStatus.SupportedNotInstalled:
             _ShowAndroidToastMessage("Supported, not installed, requesting installation");
             Session.RequestApkInstallation(false);
             break;
         case ApkAvailabilityStatus.UnknownChecking:
             _ShowAndroidToastMessage("Unknown Checking");
             break;
         case ApkAvailabilityStatus.UnknownError:
             _ShowAndroidToastMessage("Unknown Error");
             break;
         case ApkAvailabilityStatus.UnknownTimedOut:
             _ShowAndroidToastMessage("Unknown Timed out");
             break;
         case ApkAvailabilityStatus.UnsupportedDeviceNotCapable:
             _ShowAndroidToastMessage("Unsupported Device Not Capable");
             break;
     }
 }
 

All you need is to call StartCoroutine(CheckCompatibility()); from Start method (_ShowAndroidToastMessage method taken from ComputerVisionController class)