1 files changed, 2 insertions, 1 deletions
diff --git a/libs/PiwikTracker/PiwikTracker.php b/libs/PiwikTracker/PiwikTracker.php
index 8605e38e1f..15e3b8420c 100644
--- a/libs/PiwikTracker/PiwikTracker.php
+++ b/libs/PiwikTracker/PiwikTracker.php
@@ -1063,6 +1063,8 @@ class PiwikTracker
     /**
      * Hash function used internally by Piwik to hash a User ID into the Visitor ID.
      *
+     * Note: matches implementation of Tracker\Request->getUserIdHashed()
+     *
      * @param $id
      * @return string
      */
@@ -1071,7 +1073,6 @@ class PiwikTracker
         return substr( sha1( $id ), 0, 16);
     }
 
-
     /**
      * Forces the requests to be recorded for the specified Visitor ID.
      * Note: it is recommended to use ->setUserId($userId); instead.