The decision has been made to deprecate + sunset this project, since:

• Configuring Django for Heroku does not actually require many changes (eg reading DATABASES_URL and setting up WhiteNoise - which already has great docs), so does not really need a complex helper package to achieve this.
• Hiding settings in a package makes it harder for users to understand what is actually happening, hindering debugging, and making it more confusing when wanting to override parts of django-heroku but not others. And IMO it's against Python's "explicit is better than implicit" mentality.
• Having the config as a package brings with it a bunch of maintenance/compatibility concerns. For example, does this package have to support multiple versions of Django, or do we only support latest, and then have to make sure users check a support matrix of compatible versions first? Or, how do users use a brand new (or even beta) version of Django, until we've had time to update the package?

To migrate away from django-heroku, inline the config it used to set in your settings.py.

An example of doing that can be seen here, in the commit that migrated Heroku's Getting Started on Python guide away from the package:
heroku/python-getting-started@14230b2

If you happened to use one of the opt-in/more advanced django-heroku features such as db_colors=True, then inline those parts of the config as needed. You can find django-heroku's original full config here:
https://github.com/heroku/django-heroku/blob/v0.3.0/django_heroku/core.py

(Note: The latest version of django-heroku on the master branch is actually slightly broken, and doesn't match the published release on PyPI. To see what's on PyPI, make sure to view on GitHub via the v0.3.0 Git tag - as the link above does.)