diff --git a/django_mailbox/signals.py b/django_mailbox/signals.py
index b445183..9af4af7 100644
--- a/django_mailbox/signals.py
+++ b/django_mailbox/signals.py
@@ -1,3 +1,3 @@
 from django.dispatch.dispatcher import Signal
 
-message_received = Signal(providing_args=['message'])
+message_received = Signal()
diff --git a/django_mailbox/south_migrations/0006_auto__add_field_message_in_reply_to.py b/django_mailbox/south_migrations/0006_auto__add_field_message_in_reply_to.py
index 4287fb2..9c17019 100644
--- a/django_mailbox/south_migrations/0006_auto__add_field_message_in_reply_to.py
+++ b/django_mailbox/south_migrations/0006_auto__add_field_message_in_reply_to.py
@@ -15,8 +15,8 @@ class Migration(SchemaMigration):
         # Adding M2M table for field references on 'Message'
         db.create_table('django_mailbox_message_references', (
             ('id', models.AutoField(verbose_name='ID', primary_key=True, auto_created=True)),
-            ('from_message', models.ForeignKey(orm['django_mailbox.message'], null=False)),
-            ('to_message', models.ForeignKey(orm['django_mailbox.message'], null=False))
+            ('from_message', models.ForeignKey(orm['django_mailbox.message'], on_delete=models.CASCADE,  null=False)),
+            ('to_message', models.ForeignKey(orm['django_mailbox.message'], on_delete=models.CASCADE,  null=False))
         ))
         db.create_unique('django_mailbox_message_references', ['from_message_id', 'to_message_id'])
 
diff --git a/django_mailbox/south_migrations/0009_remove_references_table.py b/django_mailbox/south_migrations/0009_remove_references_table.py
index 3868585..70cf0de 100644
--- a/django_mailbox/south_migrations/0009_remove_references_table.py
+++ b/django_mailbox/south_migrations/0009_remove_references_table.py
@@ -15,8 +15,8 @@ class Migration(SchemaMigration):
         # Adding M2M table for field references on 'Message'
         db.create_table('django_mailbox_message_references', (
             ('id', models.AutoField(verbose_name='ID', primary_key=True, auto_created=True)),
-            ('from_message', models.ForeignKey(orm['django_mailbox.message'], null=False)),
-            ('to_message', models.ForeignKey(orm['django_mailbox.message'], null=False))
+            ('from_message', models.ForeignKey(orm['django_mailbox.message'], on_delete=models.CASCADE,  null=False)),
+            ('to_message', models.ForeignKey(orm['django_mailbox.message'], on_delete=models.CASCADE,  null=False))
         ))
         db.create_unique('django_mailbox_message_references', ['from_message_id', 'to_message_id'])
 
diff --git a/django_mailbox/south_migrations/0012_auto__add_messageattachment.py b/django_mailbox/south_migrations/0012_auto__add_messageattachment.py
index b62e50e..945be81 100644
--- a/django_mailbox/south_migrations/0012_auto__add_messageattachment.py
+++ b/django_mailbox/south_migrations/0012_auto__add_messageattachment.py
@@ -17,8 +17,8 @@ class Migration(SchemaMigration):
         # Adding M2M table for field attachments on 'Message'
         db.create_table('django_mailbox_message_attachments', (
             ('id', models.AutoField(verbose_name='ID', primary_key=True, auto_created=True)),
-            ('message', models.ForeignKey(orm['django_mailbox.message'], null=False)),
-            ('messageattachment', models.ForeignKey(orm['django_mailbox.messageattachment'], null=False))
+            ('message', models.ForeignKey(orm['django_mailbox.message'], on_delete=models.CASCADE,  null=False)),
+            ('messageattachment', models.ForeignKey(orm['django_mailbox.messageattachment'], on_delete=models.CASCADE,  null=False))
         ))
         db.create_unique('django_mailbox_message_attachments', ['message_id', 'messageattachment_id'])
 
diff --git a/django_mailbox/south_migrations/0015_auto__add_field_messageattachment_headers.py b/django_mailbox/south_migrations/0015_auto__add_field_messageattachment_headers.py
index 71ecfbd..da15c66 100644
--- a/django_mailbox/south_migrations/0015_auto__add_field_messageattachment_headers.py
+++ b/django_mailbox/south_migrations/0015_auto__add_field_messageattachment_headers.py
@@ -20,8 +20,8 @@ class Migration(SchemaMigration):
         # Adding M2M table for field attachments on 'Message'
         db.create_table('django_mailbox_message_attachments', (
             ('id', models.AutoField(verbose_name='ID', primary_key=True, auto_created=True)),
-            ('message', models.ForeignKey(orm['django_mailbox.message'], null=False)),
-            ('messageattachment', models.ForeignKey(orm['django_mailbox.messageattachment'], null=False))
+            ('message', models.ForeignKey(orm['django_mailbox.message'], on_delete=models.CASCADE,  null=False)),
+            ('messageattachment', models.ForeignKey(orm['django_mailbox.messageattachment'], on_delete=models.CASCADE,  null=False))
         ))
         db.create_unique('django_mailbox_message_attachments', ['message_id', 'messageattachment_id'])
 
diff --git a/django_mailbox/tests/test_process_email.py b/django_mailbox/tests/test_process_email.py
index a6dbd04..ee71f4c 100644
--- a/django_mailbox/tests/test_process_email.py
+++ b/django_mailbox/tests/test_process_email.py
@@ -9,7 +9,7 @@ from django_mailbox.models import Mailbox, Message
 from django_mailbox.utils import convert_header_to_unicode
 from django_mailbox import utils
 from django_mailbox.tests.base import EmailMessageTestCase
-from django.utils.encoding import force_text
+from django.utils.encoding import force_str
 from django.core.mail import EmailMessage
 
 __all__ = ['TestProcessEmail']
@@ -367,12 +367,12 @@ class TestProcessEmail(EmailMessageTestCase):
         email_object = self._get_email_object(
             'message_with_long_content.eml',
         )
-        size = len(force_text(email_object.as_string()))
+        size = len(force_str(email_object.as_string()))
 
         msg = self.mailbox.process_incoming_message(email_object)
 
         self.assertEqual(size,
-                         len(force_text(msg.get_email_object().as_string())))
+                         len(force_str(msg.get_email_object().as_string())))
 
     def test_message_saved(self):
         message = self._get_email_object('generic_message.eml')
diff --git a/docs/conf.py b/docs/conf.py
index 974706f..c015980 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -244,7 +244,7 @@ sys.path.insert(0, os.path.abspath('..'))
 import inspect
 import django
 from django.utils.html import strip_tags
-from django.utils.encoding import force_text
+from django.utils.encoding import force_str
 from django.conf import settings
 settings.configure(INSTALLED_APPS=['django_mailbox', ])
 django.setup()
@@ -265,11 +265,11 @@ def process_docstring(app, what, name, obj, options, lines):
                 continue
 
             # Decode and strip any html out of the field's help text
-            help_text = strip_tags(force_text(field.help_text))
+            help_text = strip_tags(force_str(field.help_text))
 
             # Decode and capitalize the verbose name, for use if there isn't
             # any help text
-            verbose_name = force_text(field.verbose_name).capitalize()
+            verbose_name = force_str(field.verbose_name).capitalize()
 
             if help_text:
                 # Add the model field to the end of the docstring as a param