diff --git a/docs/LennyToSqueeze.xml b/docs/LennyToSqueeze.xml
index 5b7ecc81a..1a0d09bd2 100644
--- a/docs/LennyToSqueeze.xml
+++ b/docs/LennyToSqueeze.xml
@@ -135,6 +135,12 @@
       </listitem>
     </orderedlist>
 
+    <warning>
+      <para>Do not purge the old packages (shorewall-common, shorewall-shell
+      and shorewall-perl) until after the new shorewall package has been
+      installed.</para>
+    </warning>
+
     <para>The key change in Squeeze that may produce upgrade issues is that
     Squeeze does not include the shell-based configuration compiler. As a
     consequence, unless you have migrated to using Shorewall-perl on Lenny, an