Index: src/wp-includes/feed-atom-comments.php
===================================================================
--- src/wp-includes/feed-atom-comments.php	(revision 39533)
+++ src/wp-includes/feed-atom-comments.php	(working copy)
@@ -43,7 +43,7 @@
 
 	<updated><?php
 		$date = get_lastcommentmodified( 'GMT' );
-		echo $date ? mysql2date( 'Y-m-d\TH:i:s\Z', $date ) : date( 'Y-m-d\TH:i:s\Z' );
+		echo $date ? mysql2date( 'Y-m-d\TH:i:s\Z', $date, false ) : date( 'Y-m-d\TH:i:s\Z' );
 	?></updated>
 
 <?php if ( is_singular() ) { ?>
Index: src/wp-includes/feed-atom.php
===================================================================
--- src/wp-includes/feed-atom.php	(revision 39533)
+++ src/wp-includes/feed-atom.php	(working copy)
@@ -32,7 +32,7 @@
 
 	<updated><?php
 		$date = get_lastpostmodified( 'GMT' );
-		echo $date ? mysql2date( 'Y-m-d\TH:i:s\Z', $date ) : date( 'Y-m-d\TH:i:s\Z' );
+		echo $date ? mysql2date( 'Y-m-d\TH:i:s\Z', $date, false ) : date( 'Y-m-d\TH:i:s\Z' );
 	?></updated>
 
 	<link rel="alternate" type="<?php bloginfo_rss('html_type'); ?>" href="<?php bloginfo_rss('url') ?>" />
Index: src/wp-includes/feed-rss2-comments.php
===================================================================
--- src/wp-includes/feed-rss2-comments.php	(revision 39533)
+++ src/wp-includes/feed-rss2-comments.php	(working copy)
@@ -49,7 +49,7 @@
 	<description><?php bloginfo_rss("description") ?></description>
 	<lastBuildDate><?php
 		$date = get_lastcommentmodified( 'GMT' );
-		echo $date ? mysql2date( 'r', $date ) : date( 'r' );
+		echo $date ? mysql2date( 'r', $date, false ) : date( 'r' );
 	?></lastBuildDate>
 	<sy:updatePeriod><?php
 		/** This filter is documented in wp-includes/feed-rss2.php */
Index: src/wp-includes/feed-rss2.php
===================================================================
--- src/wp-includes/feed-rss2.php	(revision 39533)
+++ src/wp-includes/feed-rss2.php	(working copy)
@@ -44,7 +44,7 @@
 	<description><?php bloginfo_rss("description") ?></description>
 	<lastBuildDate><?php
 		$date = get_lastpostmodified( 'GMT' );
-		echo $date ? mysql2date( 'D, d M Y H:i:s +0000', $date ) : date( 'D, d M Y H:i:s +0000' );
+		echo $date ? mysql2date( 'D, d M Y H:i:s +0000', $date, false ) : date( 'D, d M Y H:i:s +0000' );
 	?></lastBuildDate>
 	<language><?php bloginfo_rss( 'language' ); ?></language>
 	<sy:updatePeriod><?php