thinking about it more deeply now I think this is a breaking change. Ideally I should find a way to change things such that this settings file change is not needed.
If it turns out to be needed and hard to avoid, the release notes should add some text about needing to add this to their own settings.
This was determined to be a breaking change and pretty hard to avoid without introducing issues, and I added a notice about it into the 1.8.0 release notes
When preparing the Django 1.11 support patch I ended up
https://github.com/jazzband/django-floppyforms/blob/967e53c82dbd520b9e2c91b2d216eab648dc2f7e/tests/settings.py#L35
thinking about it more deeply now I think this is a breaking change. Ideally I should find a way to change things such that this settings file change is not needed.
If it turns out to be needed and hard to avoid, the release notes should add some text about needing to add this to their own settings.