Index: wordpress2.2/wp-includes/feed-atom.php
===================================================================
--- wordpress2.2/wp-includes/feed-atom.php	(revision 5942)
+++ wordpress2.2/wp-includes/feed-atom.php	(working copy)
@@ -33,7 +33,7 @@
 		<title type="<?php html_type_rss(); ?>"><![CDATA[<?php the_title_rss() ?>]]></title>
 		<link rel="alternate" type="text/html" href="<?php the_permalink_rss() ?>" />
 		<id><?php the_guid(); ?></id>
-		<updated><?php echo get_post_time('Y-m-d\TH:i:s\Z', true); ?></updated>
+		<updated><?php echo get_post_modified_time('Y-m-d\TH:i:s\Z', true); ?></updated>
 		<published><?php echo get_post_time('Y-m-d\TH:i:s\Z', true); ?></published>
 		<?php the_category_rss('atom') ?>
 		<summary type="<?php html_type_rss(); ?>"><![CDATA[<?php the_excerpt_rss(); ?>]]></summary>