diff --git a/address.py b/address.py
index 1e1b9ae183..b48b46fd1f 100644
--- a/address.py
+++ b/address.py
@@ -63,9 +63,6 @@ class Address(DeactivableMixin, sequence_ordered(), ModelSQL, ModelView):
 
         table = cls.__table_handler__(module_name)
 
-        # Migration from 2.4: drop required on sequence
-        table.not_null_action('sequence', action='remove')
-
         # Migration from 4.0: remove streetbis
         if table.column_exist('streetbis'):
             value = Concat(
diff --git a/contact_mechanism.py b/contact_mechanism.py
index 0c216f5d70..3c13f957c8 100644
--- a/contact_mechanism.py
+++ b/contact_mechanism.py
@@ -101,15 +101,6 @@ class ContactMechanism(
                     'party "%(party)s" is not valid .'),
                 })
 
-    @classmethod
-    def __register__(cls, module_name):
-        super(ContactMechanism, cls).__register__(module_name)
-
-        table = cls.__table_handler__(module_name)
-
-        # Migration from 2.4: drop required on sequence
-        table.not_null_action('sequence', action='remove')
-
     @staticmethod
     def default_type():
         return 'phone'