Connecting Django Signals using the AppConfig ready handler: https://docs.djangoproject.com/en/1.10/ref/applications/#django.apps.AppConfig.ready

__init__.py

default_app_config = 'cn.apps.users.config.UsersAppConfig'

config.py

from django.apps import AppConfig


class UsersAppConfig(AppConfig):
    name = 'cn.apps.users'

    def ready(self):
        import signals  # noqa

signals.py

from django.dispatch import receiver
from django.db.models.signals import post_save, pre_delete
from django.contrib.auth.models import User

from .models import UserProfile


@receiver(post_save, sender=User, dispatch_uid="users.create_user_profile")
def create_user_profile(**kwargs):
    """
    Automatically create a UserProfile for any newly created User.
    """
    user = kwargs.get('instance')
    if not hasattr(user, 'profile'):
        UserProfile.objects.create(user=user)


@receiver(pre_delete, sender=UserProfile,
          dispatch_uid="profiles.delete_profile_image")
def delete_profile_image(**kwargs):
    """
    Deletes the UserProfile.image file.
    """
    kwargs.get('instance').image.delete(save=False)

As per the documentation, it's recommended to avoid using default_app_config in __init__.py and require cn.apps.users.config.UsersAppConfig in INSTALLED_APPS

New applications should avoid default_app_config. Instead they should require the dotted path to the appropriate AppConfig subclass to be configured explicitly in INSTALLED_APPS.

INSTALLED_APPS = [
   ...
    'cn.apps.users.config.UsersAppConfig',
   ...
]

thanks guys, this has solved my issue with signals in Django 3