diff --git a/golem_activity_registration_payment/__manifest__.py b/golem_activity_registration_payment/__manifest__.py
index 99193bf..2363982 100644
--- a/golem_activity_registration_payment/__manifest__.py
+++ b/golem_activity_registration_payment/__manifest__.py
@@ -20,7 +20,7 @@
     'name': 'GOLEM Activity Member Registration Payments',
     'summary': 'GOLEM Activities Member Registration Payments',
     'description': 'GOLEM Activities Member Registration Payments',
-    'version': '10.0.0.4.0',
+    'version': '10.0.0.4.1',
     'category': 'GOLEM',
     'author': 'Fabien Bourgeois',
     'license': 'AGPL-3',
diff --git a/golem_activity_registration_payment/wizard/golem_activity_registration_invoicing.py b/golem_activity_registration_payment/wizard/golem_activity_registration_invoicing.py
index d21b3b4..6454666 100644
--- a/golem_activity_registration_payment/wizard/golem_activity_registration_invoicing.py
+++ b/golem_activity_registration_payment/wizard/golem_activity_registration_invoicing.py
@@ -29,9 +29,11 @@ class GolemActivityRegistrationInvoicingLine(models.TransientModel):
     _description = 'GOLEM Activity Registration Invoicing Lines'
 
     invoicing_id = fields.Many2one('golem.activity.registration.invoicing',
-                                   required=True)
-    registration_id = fields.Many2one('golem.activity.registration', required=True)
-    activity_id = fields.Many2one('golem.activity', required=True, readonly=True)
+                                   required=True, ondelete='cascade')
+    registration_id = fields.Many2one('golem.activity.registration', required=True,
+                                      ondelete='cascade')
+    activity_id = fields.Many2one('golem.activity', required=True, readonly=True,
+                                  ondelete='cascade')
     price = fields.Monetary()
     currency_id = fields.Many2one(related='activity_id.currency_id')