diff --git a/simple_email_confirmation/__init__.py b/simple_email_confirmation/__init__.py
index 0bc25cd..14aecd3 100644
--- a/simple_email_confirmation/__init__.py
+++ b/simple_email_confirmation/__init__.py
@@ -1,13 +1,26 @@
-__version__ = '0.12'
+__version__ = '0.13'
 __all__ = [
-    'SimpleEmailConfirmationUserMixin',
-    'EmailAddress',
     'email_confirmed',
     'unconfirmed_email_created',
     'primary_email_changed',
 ]
 
-from .models import SimpleEmailConfirmationUserMixin, EmailAddress
+import django
+from django.apps import apps
+from django.conf import settings
+
 from .signals import (
     email_confirmed, unconfirmed_email_created, primary_email_changed,
 )
+
+if django.get_version() < '4':
+    default_app_config = 'simple_email_confirmation.apps.EmailAddressConfig'
+
+
+def get_email_address_model():
+    """Convenience method to return the email model being used."""
+    return apps.get_model(getattr(
+        settings,
+        'SIMPLE_EMAIL_CONFIRMATION_EMAIL_ADDRESS_MODEL',
+        'simple_email_confirmation.EmailAddress'
+    ))
diff --git a/simple_email_confirmation/admin.py b/simple_email_confirmation/admin.py
index 7df7926..529671a 100644
--- a/simple_email_confirmation/admin.py
+++ b/simple_email_confirmation/admin.py
@@ -7,4 +7,5 @@ class EmailAddressAdmin(admin.ModelAdmin):
     list_display = ('user', 'email', 'key', 'set_at', 'confirmed_at')
     search_fields = ('email', 'key')
 
+
 admin.site.register((EmailAddress,), EmailAddressAdmin)
diff --git a/simple_email_confirmation/apps.py b/simple_email_confirmation/apps.py
new file mode 100644
index 0000000..4939e75
--- /dev/null
+++ b/simple_email_confirmation/apps.py
@@ -0,0 +1,15 @@
+"""Application configuration."""
+
+from django.apps import AppConfig
+from django.utils.translation import gettext_lazy as _
+
+__all__ = ['EmailAddressConfig']
+
+
+class EmailAddressConfig(AppConfig):
+    """Default configuration for the simple_email_confirmation app."""
+
+    name = 'simple_email_confirmation'
+    label = 'simple_email_confirmation'
+    verbose_name = _('EmailAddress')
+    default_auto_field = 'django.db.models.AutoField'
diff --git a/simple_email_confirmation/migrations/0001_initial.py b/simple_email_confirmation/migrations/0001_initial.py
index 8b9d130..9b99c82 100644
--- a/simple_email_confirmation/migrations/0001_initial.py
+++ b/simple_email_confirmation/migrations/0001_initial.py
@@ -21,7 +21,7 @@ class Migration(migrations.Migration):
                 ('key', models.CharField(unique=True, max_length=40)),
                 ('set_at', models.DateTimeField(default=django.utils.timezone.now, help_text='When the confirmation key expiration was set')),
                 ('confirmed_at', models.DateTimeField(help_text='First time this email was confirmed', null=True, blank=True)),
-                ('user', models.ForeignKey(related_name='email_address_set', to=settings.AUTH_USER_MODEL)),
+                ('user', models.ForeignKey(related_name='email_address_set', to=settings.AUTH_USER_MODEL, on_delete=models.CASCADE)),
             ],
             options={
                 'verbose_name_plural': 'email addresses',
diff --git a/simple_email_confirmation/models.py b/simple_email_confirmation/models.py
index 5501162..f35c20f 100644
--- a/simple_email_confirmation/models.py
+++ b/simple_email_confirmation/models.py
@@ -1,12 +1,19 @@
 from __future__ import unicode_literals
 
+from random import randint
+
+import django
 from django.conf import settings
 from django.contrib.auth import get_user_model
 from django.db import models
 from django.db.models.signals import post_save
-from django.utils.crypto import get_random_string
 from django.utils import timezone
-from django.utils.translation import ugettext_lazy as _
+from django.utils.crypto import get_random_string
+
+if django.get_version() > '4':
+    from django.utils.translation import gettext_lazy as _
+else:
+    from django.utils.translation import ugettext_lazy as _
 
 from .exceptions import (
     EmailConfirmationExpired, EmailIsPrimary, EmailNotConfirmed,
@@ -155,7 +162,7 @@ class EmailAddressManager(models.Manager):
     def generate_key(self):
         "Generate a new random key and return it"
         # sticking with the django defaults
-        return get_random_string()
+        return get_random_string(length=randint(15, 20))
 
     def create_confirmed(self, email, user=None):
         "Create an email address in the confirmed state"
@@ -204,7 +211,7 @@ class EmailAddress(models.Model):
     "An email address belonging to a User"
 
     user = models.ForeignKey(
-        settings.AUTH_USER_MODEL, related_name='email_address_set',
+        settings.AUTH_USER_MODEL, related_name='email_address_set', on_delete=models.CASCADE
     )
     email = models.EmailField(max_length=255)
     key = models.CharField(max_length=40, unique=True)
@@ -279,6 +286,7 @@ def auto_add(sender, **kwargs):
             else:
                 user.email_address_set.create_unconfirmed(email)
 
+
     # TODO: try to only connect this to the User model. We can't use
     #       get_user_model() here - results in import loop.
 
diff --git a/simple_email_confirmation/signals.py b/simple_email_confirmation/signals.py
index f45ec28..354596c 100644
--- a/simple_email_confirmation/signals.py
+++ b/simple_email_confirmation/signals.py
@@ -1,7 +1,10 @@
 from django.dispatch import Signal
 
-email_confirmed = Signal(providing_args=['user', 'email'])
-unconfirmed_email_created = Signal(providing_args=['user', 'email'])
-primary_email_changed = Signal(
-    providing_args=['user', 'new_email', 'old_email'],
-)
+try:
+    email_confirmed = Signal(providing_args=['user', 'email'])
+    unconfirmed_email_created = Signal(providing_args=['user', 'email'])
+    primary_email_changed = Signal(providing_args=['user', 'new_email', 'old_email'])
+except TypeError:
+    email_confirmed = Signal()
+    unconfirmed_email_created = Signal()
+    primary_email_changed = Signal()