Refs -- Doc'd that on_delete is required in migrations.
@@ -681,8 +681,9 @@ these features.
* ``Field.rel`` and ``Field.remote_field.to`` are removed.
-* The ``on_delete`` argument for ``ForeignKey`` and ``OneToOneField`` are now
- required.
+* The ``on_delete`` argument for ``ForeignKey`` and ``OneToOneField`` is now
+ required in models and migrations. Consider squashing migrations so that you
+ have less of them to update.
* ``django.db.models.fields.add_lazy_relation()`` is removed.
