diff --git a/user_guide/changelog.html b/user_guide/changelog.html
index e4199cd..5608145 100644
--- a/user_guide/changelog.html
+++ b/user_guide/changelog.html
@@ -88,6 +88,7 @@
 	<li>General
 		<ul>
 			<li>Modified <a href="general/errors.html">show_error()</a> to allow sending of HTTP server response codes.</li>
+			<li>Modified <a href="general/errors.html">show_404()</a> to send 404 status code, removing non-CGI compatible header() statement from error_404.php template.</li>
 			<li>Added set_status_header() to the <a href="general/common_functions.html">Common functions<a> to allow use when the Output class is unavailable.</li>
 		</ul>
 	</li>
diff --git a/user_guide/installation/upgrade_172.html b/user_guide/installation/upgrade_172.html
new file mode 100644
index 0000000..ee775a3
--- /dev/null
+++ b/user_guide/installation/upgrade_172.html
@@ -0,0 +1,105 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
+<head>
+
+<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
+<title>Upgrading from 1.7.1 to 1.7.2 : CodeIgniter User Guide</title>
+
+<style type='text/css' media='all'>@import url('../userguide.css');</style>
+<link rel='stylesheet' type='text/css' media='all' href='../userguide.css' />
+
+<script type="text/javascript" src="../nav/nav.js"></script>
+<script type="text/javascript" src="../nav/prototype.lite.js"></script>
+<script type="text/javascript" src="../nav/moo.fx.js"></script>
+<script type="text/javascript" src="../nav/user_guide_menu.js"></script>
+
+<meta http-equiv='expires' content='-1' />
+<meta http-equiv= 'pragma' content='no-cache' />
+<meta name='robots' content='all' />
+<meta name='author' content='ExpressionEngine Dev Team' />
+<meta name='description' content='CodeIgniter User Guide' />
+
+</head>
+<body>
+
+<!-- START NAVIGATION -->
+<div id="nav"><div id="nav_inner"><script type="text/javascript">create_menu('../');</script></div></div>
+<div id="nav2"><a name="top"></a><a href="javascript:void(0);" onclick="myHeight.toggle();"><img src="../images/nav_toggle_darker.jpg" width="154" height="43" border="0" title="Toggle Table of Contents" alt="Toggle Table of Contents" /></a></div>
+<div id="masthead">
+<table cellpadding="0" cellspacing="0" border="0" style="width:100%">
+<tr>
+<td><h1>CodeIgniter User Guide Version 1.7.1</h1></td>
+<td id="breadcrumb_right"><a href="../toc.html">Table of Contents Page</a></td>
+</tr>
+</table>
+</div>
+<!-- END NAVIGATION -->
+
+
+<!-- START BREADCRUMB -->
+<table cellpadding="0" cellspacing="0" border="0" style="width:100%">
+<tr>
+<td id="breadcrumb">
+<a href="http://codeigniter.com/">CodeIgniter Home</a> &nbsp;&#8250;&nbsp;
+<a href="../index.html">User Guide Home</a> &nbsp;&#8250;&nbsp;
+Upgrading from 1.7.1 to 1.7.2
+</td>
+<td id="searchbox"><form method="get" action="http://www.google.com/search"><input type="hidden" name="as_sitesearch" id="as_sitesearch" value="codeigniter.com/user_guide/" />Search User Guide&nbsp; <input type="text" class="input" style="width:200px;" name="q" id="q" size="31" maxlength="255" value="" />&nbsp;<input type="submit" class="submit" name="sa" value="Go" /></form></td>
+</tr>
+</table>
+<!-- END BREADCRUMB -->
+
+<br clear="all" />
+
+
+<!-- START CONTENT -->
+<div id="content">
+
+<h1>Upgrading from 1.7.1 to 1.7.2</h1>
+
+<p>Before performing an update you should take your site offline by replacing the index.php file with a static one.</p>
+
+
+
+<h2>Step 1: Update your CodeIgniter files</h2>
+
+<p>Replace these files and directories in your "system" folder with the new versions:</p>
+
+<ul>
+
+<li><dfn>system/codeigniter</dfn></li>
+<li><dfn>system/database</dfn></li>
+<li><dfn>system/helpers</dfn></li>
+<li><dfn>system/language</dfn></li>
+<li><dfn>system/libraries</dfn></li>
+</ul>
+
+<p class="important"><strong>Note:</strong> If you have any custom developed files in these folders please make copies of them first.</p>
+
+<h2>Step 2: Remove header() from 404 error template</h2>
+<p>If you are using header() in your 404 error template, such as the case with the default <samp>error_404.php</samp> template shown below, remove that line of code.</p>
+
+<code>&lt;?php header(&quot;HTTP/1.1 404 Not Found&quot;); ?&gt;</code>
+
+<p>404 status headers are now properly handled in the show_404() method itself.</p>
+
+<h2>Step 2: Update your user guide</h2>
+<p>Please replace your local copy of the user guide with the new version, including the image files.</p>
+
+</div>
+<!-- END CONTENT -->
+
+
+<div id="footer">
+<p>
+Previous Topic:&nbsp;&nbsp;<a href="index.html">Installation Instructions</a>
+&nbsp;&nbsp;&nbsp;&middot;&nbsp;&nbsp;
+<a href="#top">Top of Page</a>&nbsp;&nbsp;&nbsp;&middot;&nbsp;&nbsp;
+<a href="../index.html">User Guide Home</a>&nbsp;&nbsp;&nbsp;&middot;&nbsp;&nbsp;
+Next Topic:&nbsp;&nbsp;<a href="troubleshooting.html">Troubleshooting</a>
+</p>
+<p><a href="http://codeigniter.com">CodeIgniter</a> &nbsp;&middot;&nbsp; Copyright &#169; 2006-2009 &nbsp;&middot;&nbsp; <a href="http://ellislab.com/">Ellislab, Inc.</a></p>
+</div>
+
+</body>
+</html>
\ No newline at end of file