diff --git a/contract/models/account_invoice.py b/contract/models/account_invoice.py
index f7608020..3510c354 100644
--- a/contract/models/account_invoice.py
+++ b/contract/models/account_invoice.py
@@ -8,4 +8,5 @@ class AccountInvoice(models.Model):
     _inherit = 'account.invoice'
 
     # We keep this field for migration purpose
-    old_contract_id = fields.Many2one('contract.contract')
+    old_contract_id = fields.Many2one(
+        'contract.contract', oldname='contract_id')