The situation:
After upgrading django-ses to v4.2.0, importing anything from django_ses.signals (e.g. `from django_ses.signals import bounce_received, complaint_received`) raised: RuntimeError: Model class django_ses.models.SESStat doesn't declare an explicit app_label and isn't in an application in INSTALLED_APPS. The project deliberately did not add django_ses to INSTALLED_APPS because it did not use the SES Sending Stats feature, and adding it would trigger unwanted migrations. The regression came from the blacklist feature in v4.2.0, which imported models into signals.py (and utils.py via views), forcing the app registry to load.
What actually fixes it (verified in the thread):
This was a regression in django-ses v4.2.0: importing models at the top of signals.py (and utils.py, reached via django_ses.views) forced Django to resolve the SESStat model without the app being installed. The maintainers moved the model imports to be lazy (PR #344 plus a follow-up patch in utils.py), and the reporter confirmed the fix worked. Upgrade to django-ses v4.3.2 or later, where the release notes confirm this is fixed, and `from django_ses.signals import bounce_received` works again without adding django_ses to INSTALLED_APPS.