diff --git src/wp-admin/includes/dashboard.php src/wp-admin/includes/dashboard.php
index af61be3fc1..c823bc2de8 100644
--- src/wp-admin/includes/dashboard.php
+++ src/wp-admin/includes/dashboard.php
@@ -981,7 +981,7 @@ function wp_dashboard_cached_rss_widget( $widget_id, $callback, $check_urls = ar
 	}
 
 	$locale = get_user_locale();
-	$cache_key = 'dash_' . md5( $widget_id . '_' . $locale );
+	$cache_key = 'dash_v2_' . md5( $widget_id . '_' . $locale );
 	if ( false !== ( $output = get_transient( $cache_key ) ) ) {
 		echo $output;
 		return true;