on number, when present,
            MUST include a major and minor component separated by a period (U+002E or ASCII 46). The major and minor components MUST use decimal digits (0 to 9) only.
            For example, use <code>"2.5"</code> to mean a major version of 2 and a minor version
            of 5. The use and interpretation of the version number is left at the discretion
            of the applications treating the Service Description.</dd>
      <dt>summary</dt>
      <dd>
            OPTIONAL. A S