diff --git a/lib/DateTimeImmutable.php b/lib/DateTimeImmutable.php
index d9900d92..4926da0b 100644
--- a/lib/DateTimeImmutable.php
+++ b/lib/DateTimeImmutable.php
@@ -232,6 +232,7 @@ public function add($interval): self
      * @param \DateTime $dateTime
      * @return DateTimeImmutable
      */
+    #[\ReturnTypeWillChange]
     public static function createFromMutable($dateTime): self
     {
         $date = \DateTimeImmutable::createFromMutable($dateTime);