diff --git a/core/schema.py b/core/schema.py
index ad858570..27a59159 100644
--- a/core/schema.py
+++ b/core/schema.py
@@ -4,6 +4,7 @@
 import re
 import sys
 from datetime import datetime as py_datetime
+from typing import Optional
 
 import graphene
 from core import ExtendedConnection
@@ -125,7 +126,7 @@ class Input:
         client_mutation_details = graphene.List(graphene.String)
 
     @classmethod
-    def async_mutate(cls, user, **data) -> str:
+    def async_mutate(cls, user, **data) -> Optional[str]:
         """
         This method has to be overridden in the subclasses to implement the actual mutation.
         The response should contain a boolean for success and an error message that will be saved into the DB
diff --git a/setup.py b/setup.py
index a627d16d..ff8f3b83 100644
--- a/setup.py
+++ b/setup.py
@@ -9,7 +9,7 @@
 
 setup(
     name='openimis-be-core',
-    version='1.2.0rc4',
+    version='1.2.1rc1',
     packages=find_packages(),
     include_package_data=True,
     license='GNU AGPL v3',
@@ -27,11 +27,11 @@
         'django-simple-history',
         'django-dirtyfields',
         'websocket-client'
-    ],   
+    ],
     classifiers=[
         'Environment :: Web Environment',
         'Framework :: Django',
-        'Framework :: Django :: 2.1',
+        'Framework :: Django :: 3.0',
         'Intended Audience :: Developers',
         'License :: OSI Approved :: GNU Affero General Public License v3',
         'Operating System :: OS Independent',
@@ -39,4 +39,4 @@
         'Programming Language :: Python :: 3.6',
         'Programming Language :: Python :: 3.7',
     ],
-)
\ No newline at end of file
+)