1 files changed, 2 insertions, 2 deletions
diff --git a/inc/subscription.php b/inc/subscription.php
index 4248e4b11..ecbc9ef19 100644
--- a/inc/subscription.php
+++ b/inc/subscription.php
@@ -617,7 +617,7 @@ class Subscription {
      * @param string $rev The revision of the page, set to the current revision of the page $id if not set
      * @return string
      */
-    protected function getMessageID($id, $rev = NULL) {
+    protected function getMessageID($id, $rev = null) {
         static $listid = null;
         if (is_null($listid)) {
             $server = parse_url(DOKU_URL, PHP_URL_HOST);
@@ -694,4 +694,4 @@ class Subscription {
 function subscription_addresslist(&$data) {
     $sub = new Subscription();
     $sub->notifyaddresses($data);
-}
-\ No newline at end of file
+}