docs: no default value for mod_proxy upgrade= parameter. [skip ci]
@@ -1281,7 +1281,7 @@ ProxyPass "/example" "http://backend.example.com" max=20 ttl=120 retry=300
See the documentation of this module for more details.</p>
</td></tr>
<tr><td><a id="upgrade" name="upgrade">upgrade</a></td>
- <td>WebSocket</td>
+ <td>-</td>
<td><p>Protocol accepted by <module>mod_proxy_http</module> or
<module>mod_proxy_wstunnel</module> for the HTTP Upgrade mechanism
upon negotiation by the HTTP client/browser (per
