diff --git a/includes/common.inc b/includes/common.inc
index a3c86760b..ab6e8b8f6 100644
--- a/includes/common.inc
+++ b/includes/common.inc
@@ -1102,7 +1102,7 @@ function fix_gpc_magic() {
 /**
  * Verifies the syntax of the given e-mail address.
  *
- * Empty e-mail addresses are allowed. See RFC 2822 for details.
+ * See @link http://tools.ietf.org/html/rfc5321 RFC 5321 @endlink for details.
  *
  * @param $mail
  *   A string containing an e-mail address.