diff --git a/manpages/shorewall-tcdevices.xml b/manpages/shorewall-tcdevices.xml
index ffe007dca..219391b90 100644
--- a/manpages/shorewall-tcdevices.xml
+++ b/manpages/shorewall-tcdevices.xml
@@ -1,4 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN"
+"http://www.oasis-open.org/docbook/xml/4.4/docbookx.dtd">
 <refentry>
   <refmeta>
     <refentrytitle>shorewall-tcdevices</refentrytitle>