diff --git a/htdocs/install/mysql/migration/7.0.0-8.0.0.sql b/htdocs/install/mysql/migration/7.0.0-8.0.0.sql
index 4da1c8cf408..8710b340622 100644
--- a/htdocs/install/mysql/migration/7.0.0-8.0.0.sql
+++ b/htdocs/install/mysql/migration/7.0.0-8.0.0.sql
@@ -51,6 +51,9 @@ ALTER TABLE llx_ecm_files ADD UNIQUE INDEX uk_ecm_files (filepath, filename, ent
 DROP TABLE llx_c_accountancy_category;
 DROP TABLE llx_c_accountingaccount;
 
+-- drop old postgresql unique key
+-- VPGSQL8.2 DROP INDEX llx_usergroup_rights_fk_usergroup_fk_id_key
+
 update llx_propal set fk_statut = 1 where fk_statut = -1;
 
 ALTER TABLE llx_inventory ADD COLUMN fk_user_creat integer;