Update readme

README.md

@@ -14,6 +14,8 @@ If the response code is not 2XX or the request ended with a connection error, th
 Minimum first retry will be after 10 seconds, later wait time will increase exponentially.
 If the phone is not connected to the internet, the app will wait for the connection before the next attempt.
 
+If at least one Forwarding config is created and all needed permissions granted - you should see F icon in the status bar, means the app is listening for the SMS.
+
 ### Request info
 HTTP method: POST  
 Content-type: application/json; charset=utf-8