diff --git a/docs/nmap-man-enclosure.xml b/docs/nmap-man-enclosure.xml
index 8f957ba9e..6ad6f65a2 100644
--- a/docs/nmap-man-enclosure.xml
+++ b/docs/nmap-man-enclosure.xml
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
-          "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd"
+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN"
+          "http://www.oasis-open.org/docbook/xml/4.4/docbookx.dtd"
 [
 <!ENTITY refguide SYSTEM "refguide.xml">
 <!ENTITY legal-notices SYSTEM "legal-notices.xml">