--- a/ttml1-api/Overview.src.html	Sun Sep 08 14:37:17 2013 -0600
+++ b/ttml1-api/Overview.src.html	Sun Sep 08 16:18:45 2013 -0600
@@ -104,8 +104,8 @@
 </section>
 </section>
 <section id='conformance'>
-<p>An <a title='user agent'>HTML user agent</a> that claims to support any profile of [[!TTML1]], or any subsequent version thereof, must implement
-support for the TTML Level 1 API defined herein, and, if it exposes <a>TTML content</a> to Web Applications in any fashion, then it must also expose that
+<p>An <a title='user agent'>HTML user agent</a> that claims to support any profile of [[!TTML1]], or any subsequent version thereof, MUST implement
+support for the TTML Level 1 API defined herein, and, if it exposes <a>TTML content</a> to Web Applications in any fashion, then it also MUST expose that
 content to Web Applications using this API.</p>
 </section>
 <section id='dependencies'>