'AppRegistryNotReady' error after Django Upgrade from 1.8 to 1.9 version

[vinay]

In our process of upgrading our Django project from 1.8 to 1.9 version, we removed all the deprecation warnings/errors according to Django-1.9 release notes.
But, after updating the Django version to 1.9 in the project's virtual environment, we got the following error:

raise AppRegistryNotReady("Apps aren't loaded yet.")
django.core.exceptions.AppRegistryNotReady: Apps aren't loaded yet.

We have many installed apps in the project and using PostgreSQL-9.5 database. We know that the apps which have model classes in it, cause this error to occur.
The above error even occured when connecting to the database using connection cursor:

django.db.connection.cursor().execute()

[Claude Paroz]

Django 1.9 is no longer supported, so unless you can reproduce a wrong behavior with a supported Django version, we won't consider this ticket.

I'd suggest to read TicketClosingReasons/UseSupportChannels.