Index: wp-admin/includes/schema.php
===================================================================
--- wp-admin/includes/schema.php	(revision 5811)
+++ wp-admin/includes/schema.php	(working copy)
@@ -228,17 +228,16 @@
 		add_option('uploads_use_yearmonth_folders', 1);
 		add_option('upload_path', 'wp-content/uploads');
 	}
-
 	// 2.0.3
 	add_option('secret', md5(uniqid(microtime())));
-
 	// 2.1
 	add_option('blog_public', '1');
 	add_option('default_link_category', 2);
 	add_option('show_on_front', 'posts');
-
 	// 2.2
 	add_option('tag_base');
+	// 2.3
+	add_option('rss_format', 'rss2');
 
 	// Delete unused options
 	$unusedoptions = array ('blodotgsping_url', 'bodyterminator', 'emailtestonly', 'phoneemail_separator', 'smilies_directory', 'subjectprefix', 'use_bbcode', 'use_blodotgsping', 'use_phoneemail', 'use_quicktags', 'use_weblogsping', 'weblogs_cache_file', 'use_preview', 'use_htmltrans', 'smilies_directory', 'fileupload_allowedusers', 'use_phoneemail', 'default_post_status', 'default_post_category', 'archive_mode', 'time_difference', 'links_minadminlevel', 'links_use_adminlevels', 'links_rating_type', 'links_rating_char', 'links_rating_ignore_zero', 'links_rating_single_image', 'links_rating_image0', 'links_rating_image1', 'links_rating_image2', 'links_rating_image3', 'links_rating_image4', 'links_rating_image5', 'links_rating_image6', 'links_rating_image7', 'links_rating_image8', 'links_rating_image9', 'weblogs_cacheminutes', 'comment_allowed_tags', 'search_engine_friendly_urls', 'default_geourl_lat', 'default_geourl_lon', 'use_default_geourl', 'weblogs_xml_url', 'new_users_can_blog', '_wpnonce', '_wp_http_referer', 'Update', 'action', 'rich_editing');
Index: wp-includes/functions.php
===================================================================
--- wp-includes/functions.php	(revision 5811)
+++ wp-includes/functions.php	(working copy)
@@ -790,8 +790,12 @@
 	// Remove the pad, if present.
 	$feed = preg_replace('/^_+/', '', $feed);
 
-	if ( $feed == '' || $feed == 'feed' )
-		$feed = 'rss2';
+	if ( '' == $feed || 'feed' == $feed ) {
+		$feed = get_option('rss_format');
+		
+		if ( '' == $feed )
+			$feed = 'rss2';
+	}
 
 	$hook = 'do_feed_' . $feed;
 	do_action($hook, $wp_query->is_comment_feed);