diff --git a/core/includes/common.inc b/core/includes/common.inc
index 08ce2ab..5d6d07e 100644
--- a/core/includes/common.inc
+++ b/core/includes/common.inc
@@ -651,14 +651,20 @@ function drupal_encode_path($path) {
  * @param $options
  *   An associative array of additional URL options to pass to url().
  * @param $http_response_code
- *   Valid values for an actual "goto" as per RFC 2616 section 10.3 are:
+ * The valid values are defined in RFC 2616 and the draft for the new HTTP 
+ * status codes.
+ *
+ *   @see http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.3 and
+ *        http://tools.ietf.org/html/draft-reschke-http-status-308-07*  
+ *
  *   - 301 Moved Permanently (the recommended value for most redirects)
  *   - 302 Found (default in Drupal and PHP, sometimes used for spamming search
  *         engines)
  *   - 303 See Other
  *   - 304 Not Modified
  *   - 305 Use Proxy
- *   - 307 Temporary Redirect (alternative to "503 Site Down for Maintenance")
+ *   - 307 Temporary Redirect
+ *   - 308 Permanent Redirect
  *   Note: Other values are defined by RFC 2616, but are rarely used and poorly
  *   supported.
  *