diff --git a/invoice.py b/invoice.py
index b5c5220..10b9f4a 100755
--- a/invoice.py
+++ b/invoice.py
@@ -1733,7 +1733,8 @@ class Invoice(metaclass=PoolMeta):
         if not number:
             return
         legacy_supplier_ncf = (
-            invoice.type == 'in' and re.fullmatch(r'[A-Z]\d{18}', number))
+            getattr(invoice, 'type', None) == 'in'
+            and re.fullmatch(r'[A-Z]\d{18}', number))
         if not legacy_supplier_ncf and not re.fullmatch(
                 r'(?:B\d{10}|E\d{12})', number):
             raise UserError(gettext(
diff --git a/pyproject.toml b/pyproject.toml
index 9a30535..d8c461d 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -50,6 +50,7 @@ include = [
 [tool.hatch.metadata.hooks.tryton]
 copyright = 'COPYRIGHT'
 readme = 'README.rst'
+prefixes = {account_credit_note = 'unpaismejor', account_debit_note = 'unpaismejor', account_invoice_do = 'unpaismejor'}
 
 [tool.hatch.metadata.hooks.tryton.tryton-optional-dependencies]
 test = ['proteus']