diff --git a/docs/blacklisting_support.xml b/docs/blacklisting_support.xml
index 02a38787e..f0710fe02 100644
--- a/docs/blacklisting_support.xml
+++ b/docs/blacklisting_support.xml
@@ -36,6 +36,13 @@
     </legalnotice>
   </articleinfo>
 
+  <caution>
+    <para><emphasis role="bold">This article applies to Shorewall 4.4 and
+    later. If you are running a version of Shorewall earlier than Shorewall
+    4.3.5 then please see the documentation for that
+    release.</emphasis></para>
+  </caution>
+
   <section id="Intro">
     <title>Introduction</title>