Index: modules/update/update.manager.inc
===================================================================
RCS file: /cvs/drupal/drupal/modules/update/update.manager.inc,v
retrieving revision 1.24
diff -u -r1.24 update.manager.inc
--- modules/update/update.manager.inc	29 Jul 2010 02:27:43 -0000	1.24
+++ modules/update/update.manager.inc	17 Nov 2010 07:34:45 -0000
@@ -708,8 +708,10 @@
     mkdir($cache_directory);
   }
 
-  if (!file_exists($local)) {
-    return system_retrieve_file($url, $local);
+  // Download the module file again if the local cached file is outdated.
+  // (e.g. DEV releases may be outdated after 6 hours).
+  if (!file_exists($local) || (REQUEST_TIME - filectime($local)) > DRUPAL_MAXIMUM_TEMP_FILE_AGE) {
+    return system_retrieve_file($url, $local, FALSE, FILE_EXISTS_REPLACE);
   }
   else {
     return $local;