title: Difference between AFJSONRequestSerializer and AFHTTPRequestSerializer
body: <p>What actually is the reason that my request works for <code>AFJSONRequestSerializer</code> and doesnt for <code>AFHTTPRequestSerializer</code>?</p>
  
  <p>I have set   </p>
  
  <pre><code>responseSerializer.acceptableContentTypes?.insert("application/json")
  </code></pre>
  
  <p>for <code>AFHTTPRequestSerializer</code> and it doesn't work, but should.</p>
  
  <p>I just send simple dictionary:</p>
  
  <pre><code>{
      "approval_required" = 1;
      birthdate = "2016-03-11";
      gender = male;
      name = Bartolo;
      password = password1234;
      username = "super user";
  }
  </code></pre>
  
  <p><a href="https://stackoverflow.com/questions/20385353/afnetworking-2-0-cannot-post-with-json-from-ios">Here</a> is similar question, but there is no explanation <strong>WHY</strong> it is like that. </p>
  
  <p><strong>Can anyone explain?</strong></p>