diff --git a/htdocs/compta/facture/class/facture.class.php b/htdocs/compta/facture/class/facture.class.php
index 24d4b40d339..30a607afc0a 100644
--- a/htdocs/compta/facture/class/facture.class.php
+++ b/htdocs/compta/facture/class/facture.class.php
@@ -4713,7 +4713,7 @@ class Facture extends CommonInvoice
 	 * Currently used for documents generation : to know if retained warranty need to be displayed
 	 * @return bool
 	 */
-	function displayRetainedWarranty()
+	public function displayRetainedWarranty()
 	{
 		global $conf;