diff --git a/frameworks/PHP/flight/server.php b/frameworks/PHP/flight/server.php
index e7bad5ffcf9..dd5ce42c6dd 100644
--- a/frameworks/PHP/flight/server.php
+++ b/frameworks/PHP/flight/server.php
@@ -36,9 +36,9 @@ class HeaderDate
 
     public static function init(): void
     {
-        self::$date = self::NAME.gmdate('D, d M Y H:i:s').' GMT';
+        self::$date = self::NAME . gmdate(DATE_RFC7231);
         Timer::add(1, static function () {
-            self::$date = self::NAME.gmdate('D, d M Y H:i:s').' GMT';
+            self::$date = self::NAME . gmdate(DATE_RFC7231);
         });
     }
 }