diff --git a/htdocs/core/class/commondocgenerator.class.php b/htdocs/core/class/commondocgenerator.class.php
index da529e33d0e..8b79bf82d36 100644
--- a/htdocs/core/class/commondocgenerator.class.php
+++ b/htdocs/core/class/commondocgenerator.class.php
@@ -5,7 +5,7 @@
  * Copyright (C) 2005-2012	Regis Houssin           <regis.houssin@inodbox.com>
  * Copyright (C) 2015       Marcos García           <marcosgdf@gmail.com>
  * Copyright (C) 2016       Charlie Benke           <charlie@patas-monkey.com>
- * Copyright (C) 2018-2020  Frédéric France         <frederic.france@netlogic.fr>
+ * Copyright (C) 2018-2023  Frédéric France         <frederic.france@netlogic.fr>
  * Copyright (C) 2020       Josep Lluís Amador      <joseplluis@lliuretic.cat>
  *
  * This program is free software; you can redistribute it and/or modify
@@ -65,6 +65,11 @@ abstract class CommonDocGenerator
 	 */
 	public $scandir;
 
+	/**
+	 * @var array
+	 */
+	public $format;
+
 	public $page_hauteur;
 	public $page_largeur;
 	public $marge_gauche;