diff --git a/src/Enum.php b/src/Enum.php
index 6967ab5..382e1c4 100644
--- a/src/Enum.php
+++ b/src/Enum.php
@@ -311,6 +311,7 @@ public static function __callStatic($name, $arguments)
      * @link http://php.net/manual/en/jsonserializable.jsonserialize.php
      * @psalm-pure
      */
+    #[\ReturnTypeWillChange]
     public function jsonSerialize()
     {
         return $this->getValue();