Add a compatibility note
[skip ci]
</table>
</note>
+<note><title>Compatibility:</title>
+ <p><code>OPTIONS11</code>, <code>HEAD11</code> and <code>GET11</code> are
+ available in 2.4.55 and above.</p>
+</note>
+
</summary>
<seealso><module>mod_proxy</module></seealso>
