diff --git a/account_banking_mandate/__manifest__.py b/account_banking_mandate/__manifest__.py
index 5e4667e34..6022c2d99 100644
--- a/account_banking_mandate/__manifest__.py
+++ b/account_banking_mandate/__manifest__.py
@@ -8,7 +8,7 @@
 {
     'name': 'Account Banking Mandate',
     'summary': 'Banking mandates',
-    'version': '10.0.1.1.5',
+    'version': '10.0.1.1.6',
     'license': 'AGPL-3',
     'author': "Compassion CH, "
               "Tecnativa, "
diff --git a/account_banking_mandate/models/account_banking_mandate.py b/account_banking_mandate/models/account_banking_mandate.py
index 884809606..e6484fa4c 100644
--- a/account_banking_mandate/models/account_banking_mandate.py
+++ b/account_banking_mandate/models/account_banking_mandate.py
@@ -75,7 +75,7 @@ class AccountBankingMandate(models.Model):
                       ) % mandate.unique_mandate_reference)
 
     @api.multi
-    @api.constrains('state', 'partner_bank_id')
+    @api.constrains('state', 'partner_bank_id', 'signature_date')
     def _check_valid_state(self):
         for mandate in self:
             if mandate.state == 'valid':