.</li>
      <li>Add <code>version</code> member to Procedure Call and Procedure Return objects.</li>
      <li>Formalization of the JSON type system, i.e. Boolean, String, Number, Array, Object and
            the Null value (capitalization significant).</li>
      <li>Added call encoding for HTTP GET.</li>
      <li>Added named and positional arguments. </li>
      <li>Added Error object and formalization of error codes. </li>
      <li>Added introspection (service description) and required system procedu