title: I'm getting error Upgrade Required while integrating twilio whatsapp in c#
body: <p>This is the error I am  getting while trying to send the message.</p>
  
  <blockquote>
    <p>An unhandled exception of type 'Twilio.Exceptions.ApiException'
    occurred in Twilio.dll<br>
        Additional information: Upgrade Required</p>
  </blockquote>
  
  <p>My code is:</p>
  
  <pre><code>const string accountSid = "Value";
  const string authToken = "Value";
  TwilioClient.Init(accountSid, authToken);
  var to = new PhoneNumber("+whatsapp:+13233633791");
  var message = MessageResource.Create(
      to,
      from: new PhoneNumber("+whatsapp:+12037179461"),
      body: "Hi Joe! Your order D45987AB will arrive on 8/12/2018 before 8 pm.");
      Console.WriteLine(message.Sid);
  </code></pre>