diff --git a/SecurityPolicy.html b/SecurityPolicy.html
index eddbc06..9772099 100644
--- a/SecurityPolicy.html
+++ b/SecurityPolicy.html
@@ -1,11 +1,12 @@
-<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
-                      "http://www.w3.org/TR/html4/loose.dtd">
-<html>
+<?xml version="1.0" encoding="utf-8"?>
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"
+	"http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml">
  <head>
- <meta http-equiv="CONTENT-TYPE" content="text/html; charset=utf-8">
+ <meta http-equiv="CONTENT-TYPE" content="text/html; charset=utf-8" />
  <title>Security Policy - work-in-progress</title>
 
-<style type="text/css">
+<style type="text/css">  <!-- only for WIP -->
 <!--
 body {
 	font-family : verdana, helvetica, arial, sans-serif;
@@ -55,7 +56,7 @@ a:hover {
 </ul>
 
 <p>
-WIP Changes are all marked in <span class="change">BLUE</span> or <s>struck-out</s>.</span>
+WIP Changes are all marked in <span class="change">BLUE</span> or <span class="change"><s>struck-out</s>.</span>
 Explanatory comments in <span class="q">GREEN</span> are not part of text.<br />
 </p>
 
@@ -1430,5 +1431,5 @@ Relevant and helpful Documents should be referenced for convenience.
 
 <hr>
 <a href="http://validator.w3.org/check?uri=referer"><img src="Images/valid-html401-blue.png" id="graphics2" alt="Valid HTML 4.01" align="right" border="0" height="33" width="90"></a>
-<p>This is the end of the Security Policy.</p>
+<p class="q">This is the end of the Security Policy.</p>
 </body></html>
