diff --git a/pack.inc.php b/pack.inc.php
index 2c1045f..2c41b49 100644
--- a/pack.inc.php
+++ b/pack.inc.php
@@ -307,9 +307,9 @@ function config_pack_and_write_bundle(
   /*var ConfBase[]*/
   array $configs, 
   string $file_path, 
+  int $version,
   bool $use_lz4 = true, 
   int $binary_format = 1, 
-  ?int $version = null
 )
 {
   $cache_entries = array();