diff --git a/flight/Engine.php b/flight/Engine.php
index aaaf778..b0ae09d 100644
--- a/flight/Engine.php
+++ b/flight/Engine.php
@@ -575,6 +575,7 @@ class Engine
      * @param ?int $code HTTP status code
      *
      * @throws Exception
+     * @deprecated 3.5.3 This method will be removed in v4
      */
     public function _stop(?int $code = null): void
     {