diff --git a/htdocs/core/modules/contract/doc/pdf_strato.modules.php b/htdocs/core/modules/contract/doc/pdf_strato.modules.php
index 658a1104a31..a5fb5ace0f3 100644
--- a/htdocs/core/modules/contract/doc/pdf_strato.modules.php
+++ b/htdocs/core/modules/contract/doc/pdf_strato.modules.php
@@ -37,6 +37,7 @@ require_once DOL_DOCUMENT_ROOT.'/core/lib/company.lib.php';
 require_once DOL_DOCUMENT_ROOT.'/core/lib/pdf.lib.php';
 require_once DOL_DOCUMENT_ROOT.'/core/lib/date.lib.php';
 require_once DOL_DOCUMENT_ROOT.'/product/class/product.class.php';
+require_once DOL_DOCUMENT_ROOT.'/core/lib/functions2.lib.php';
 
 
 /**