diff --git a/Event/TrackableEventInterface.php b/Event/TrackableEventInterface.php
index 4de6190..ef57af5 100644
--- a/Event/TrackableEventInterface.php
+++ b/Event/TrackableEventInterface.php
@@ -10,10 +10,10 @@ interface TrackableEventInterface
     /**
      * @return int
      */
-    public function getTargetIdentifier();
+    public function getTargetIdentifier(): int;
 
     /**
      * @return string
      */
-    public function getName();
+    public function getName(): string;
 }