diff --git a/lib/TrackingStatus.lib.php b/lib/TrackingStatus.lib.php
index 9c3f7ee..fef62bb 100644
--- a/lib/TrackingStatus.lib.php
+++ b/lib/TrackingStatus.lib.php
@@ -270,6 +270,7 @@ class TrackingStatus {
             case "AC":
             case "AD":
             case "AF":
+            case "AO":
             case "AP":
             case "AR":
             case "AX":