diff --git a/htdocs/install/mysql/migration/19.0.0-20.0.0.sql b/htdocs/install/mysql/migration/19.0.0-20.0.0.sql
index d3bdc300ad4..9f5d1f13aa0 100644
--- a/htdocs/install/mysql/migration/19.0.0-20.0.0.sql
+++ b/htdocs/install/mysql/migration/19.0.0-20.0.0.sql
@@ -32,6 +32,11 @@
 -- -- VPGSQL8.2 SELECT dol_util_rebuild_sequences();
 
 
+-- V18 forgotten
+
+UPDATE llx_paiement SET ref = rowid WHERE ref IS NULL OR ref = '';
+
+
 -- V19 forgotten
 
 ALTER TABLE llx_resource ADD COLUMN phone varchar(255) DEFAULT NULL AFTER max_users;