diff --git a/core/lib/Drupal/Core/Hook/Attribute/Hook.php b/core/lib/Drupal/Core/Hook/Attribute/Hook.php
index c404a4a028bae97548af1bfe72266a5760f6fe8e..34dbc8ebf916693239a23c2640d3a60d21eef6db 100644
--- a/core/lib/Drupal/Core/Hook/Attribute/Hook.php
+++ b/core/lib/Drupal/Core/Hook/Attribute/Hook.php
@@ -135,7 +135,7 @@ public function __construct(
     public string $hook = '',
     public string $method = '',
     public ?string $module = NULL,
-    public OrderInterface|null $order = NULL,
+    public ?OrderInterface $order = NULL,
   ) {
     $this->hook = implode('_', array_filter([static::PREFIX, $hook, static::SUFFIX]));
     if ($this->hook === '') {