Activity.kt

override fun onCreate(savedInstanceState: Bundle?) {
	..
	forceUpdate = remoteConfig().getBoolean(FORCE_UPDATE)
	remoteConfig().fetchAndActivate().addOnSuccessListener {
            checkInAppUpdate()
        }
	..
}

private fun checkInAppUpdate(){
	..
	appUpdateManager.startUpdateFlowForResult(
		appUpdateInfo,
		if(forceUpdate) AppUpdateType.IMMEDIATE else AppUpdateType.FLEXIBLE,
		this,
		IN_APP_UPDATE_REQUEST_CODE
	)
	..
}

override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
	super.onActivityResult(requestCode, resultCode, data)
	 when (requestCode) {
	 	IN_APP_UPDATE_REQUEST_CODE -> {
			when(resultCode){
				//close the app if user closes immediate update
				Activity.RESULT_CANCELED -> {
				 	if(forceUpdate) finishAffinity()
				}
			}
		}
	}
}