Updates to hosting docs inline with policy changes

chrome/common/extensions/docs/templates/articles/autoupdate.html

 <h1>Autoupdating</h1>
 
 
 <p>We want extensions and apps to be autoupdated for some of the same reasons as Google Chrome itself: to incorporate bug and security fixes, add new features or performance enhancements, and improve user interfaces.</p>
 
 <p>If you publish using the <a href="https://chrome.google.com/webstore/developer/dashboard">Chrome Developer Dashboard</a>, you can <em>ignore this page</em>. You can use the dashboard to release updated versions to users, as well as to the Chrome Web Store.</p>
 
 <p>If you want to host somewhere other than the store, keep reading.
 You should also read <a href="hosting.html">Hosting</a> and
 <a href="packaging.html">Packaging</a>.</p>
 
+<p class="warning"><b>Warning:</b>
+As of M33,
+Windows stable/beta channel users can only download extensions hosted
+in the Chrome Web Store (see
+<a href="http://blog.chromium.org/2013/11/protecting-windows-users-from-malicious.html">Protecting Windows users from malicious extensions</a>).
+</p>
+ 
+<p>
+Previously when off-store extensions were supported,
+it was possible to have the native binaries and the extension be updated in lock step.
+However, extensions hosted on the Chrome Web Store are updated
+via the Chrome update mechanism which developers do not control.
+Extension developers should be careful about updating extensions
+that have a dependency on the native binary
+(for example, legacy extensions using <a href="npapi.html">NPAPI</a>).
+</p>
 
 <h2 id="overview">Overview</h2>
 <ul><li>A manifest may contain an "update_url" field, pointing to a location for doing update checks.</li>
 <li>The content returned by an update check is an <em>update manifest</em> XML document listing the latest version of an extension.</li></ul>
 
 <p>Every few hours, the browser checks whether any installed extensions or apps have an update URL. For each one, it makes a request to that URL looking for an update manifest XML file. If the update manifest mentions a version that is more recent than what's installed, the browser downloads and installs the new version. As with manual updates, the new <code>.crx</code> file must be signed with the same private key as the currently installed version.</p>
 
 
 <h2 id="update_url">Update URL</h2>
 <p>If you're hosting your own extension or app, you need to add the "update_url" field to your <a href="manifest.html"><code>manifest.json</code></a> file,
@@ skipping 126 matching lines @@
 <pre data-filename="updates.xml">
 &lt;?xml version='1.0' encoding='UTF-8'?&gt;
 &lt;gupdate xmlns='http://www.google.com/update2/response' protocol='2.0'&gt;
 &nbsp;&nbsp;&lt;app appid='aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa'&gt;
 &nbsp;&nbsp; &nbsp;&lt;updatecheck&nbsp;codebase='http://myhost.com/mytestextension/mte_v2.crx'&nbsp;version='2.0' <b>prodversionmin='3.0.193.0'</b>/&gt;
 &nbsp;&nbsp;&lt;/app&gt;
 &lt;/gupdate&gt;
 </pre>
 
 <p>This would ensure that users would autoupdate to version 2 only if they are running Google Chrome 3.0.193.0 or greater.</p>