Django 2.0 to 2.2 upgrade centos7

Question

i tried updating python from 3.4 to 3.6 changed my os from centos 6 to 7 and django from 2.0 to 2.2. i tried running

python3 manage.py check and it is working fine

System check identified no issues (0 silenced). and then tried to run server and got following exception

python3 manage.py runserver
Performing system checks...

System check identified no issues (0 silenced).
Exception in thread Thread-1:
Traceback (most recent call last):



File "/usr/lib64/python3.6/threading.py", line 916, in _bootstrap_inner
    self.run()
  File "/usr/lib64/python3.6/threading.py", line 864, in run
    self._target(*self._args, **self._kwargs)
  File "/opt/saas/venv/lib/python3.6/site-packages/django/utils/autoreload.py", line 54, in wrapper
    fn(*args, **kwargs)
  File "/opt/saas/venv/lib/python3.6/site-packages/django/core/management/commands/runserver.py", line 120, in inner_run
    self.check_migrations()
  File "/opt/saas/venv/lib/python3.6/site-packages/django/core/management/base.py", line 453, in check_migrations
    executor = MigrationExecutor(connections[DEFAULT_DB_ALIAS])
  File "/opt/saas/venv/lib/python3.6/site-packages/django/db/migrations/executor.py", line 18, in __init__
    self.loader = MigrationLoader(self.connection)
  File "/opt/saas/venv/lib/python3.6/site-packages/django/db/migrations/loader.py", line 49, in __init__
    self.build_graph()
  File "/opt/saas/venv/lib/python3.6/site-packages/django/db/migrations/loader.py", line 206, in build_graph
    self.load_disk()
  File "/opt/saas/venv/lib/python3.6/site-packages/django/db/migrations/loader.py", line 123, in load_disk
    app_config.label,
    TypeError: object() takes no parameters

please help me with this issue