org/html/rfc7230#section-6.7" target="_top"><span class="bold"><strong><code class="computeroutput"><span class="identifier">Upgrade</span></code></strong></span></a>
                </p>
              </td>
<td>
                <p>
                  The Upgrade header field provides a mechanism to transition from
                  HTTP/1.1 to another protocol on the same connection. For example,
                  it is the mechanism used by WebSocket's initial HTTP handshake
                  to establish 