diff --git a/reference/html/appendix.html b/reference/html/appendix.html
index 9cbfcfa..aecac40 100644
--- a/reference/html/appendix.html
+++ b/reference/html/appendix.html
@@ -155,7 +155,7 @@ Also, you can define your own properties.
 <tbody>
 <tr>
 <td class="tableblock halign-left valign-top"><p class="tableblock">spring.cloud.bus.ack.destination-service</p></td>
-<td class="tableblock halign-left valign-top"></td>
+<td class="tableblock halign-left valign-top"><p class="tableblock">null</p></td>
 <td class="tableblock halign-left valign-top"><p class="tableblock">Service that wants to listen to acks. By default null (meaning all services).</p></td>
 </tr>
 <tr>