diff --git a/src/Tools.php b/src/Tools.php
index b60a069..6f085c1 100755
--- a/src/Tools.php
+++ b/src/Tools.php
@@ -44,7 +44,7 @@ class Tools extends Plugin
     /**
      * @inheritdoc
      */
-    public string $schemaVersion = '3.0.3';
+    public $schemaVersion = '3.0.3';
 
     /**
      * @inheritdoc