diff --git a/.bumpversion.cfg b/.bumpversion.cfg
index 219dfa6..0e65593 100644
--- a/.bumpversion.cfg
+++ b/.bumpversion.cfg
@@ -1,8 +1,9 @@
 [bumpversion]
-current_version = 0.3.0
+current_version = 0.4.0
 commit = True
 tag = False
 
 [bumpversion:file:appveyor.yml]
+
 [bumpversion:file:setup.py]
 
diff --git a/HISTORY.rst b/HISTORY.rst
index 653271e..1dd3006 100644
--- a/HISTORY.rst
+++ b/HISTORY.rst
@@ -5,10 +5,26 @@ History
 Next Release
 ------------
 
+- Nothing yet!
+
+0.4.0 (2017-08-14)
+------------------
+
+**Warning**: This is a **breaking change**, and migrations will conflict
+with v0.3.0 due to PR `#23`_
+
 - Add UserFactory to make testing easier for developers using the
   pacakge; requires factory_boy (PR `#20`_)
+- Split the ``ImprovedIdentityMixin`` class into atomic parts:
+  ``DjangoIntegrationMixin``, ``FullNameMixin``, ``ShortNameMixin``,
+  ``EmailAuthMixin``.  This allows developers to create their own custom
+  AbstractUsers if needed. (PR `#22`_)
+- Change ``blank`` to ``True`` on ``short_name`` field of User model.
+  (**Breaking change!** PR `#23`_).
 
 .. _#20: https://github.com/jambonsw/django-improved-user/pull/20
+.. _#22: https://github.com/jambonsw/django-improved-user/pull/22
+.. _#23: https://github.com/jambonsw/django-improved-user/pull/23
 
 0.3.0 (2017-08-10)
 ------------------
diff --git a/appveyor.yml b/appveyor.yml
index 22b27e0..aa76f6c 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -1,5 +1,5 @@
 # https://www.appveyor.com/docs/appveyor-yml/
-version: '{branch}-v0.3.0-{build}'
+version: '{branch}-v0.4.0-{build}'
 branches:
   only:
   - development
diff --git a/setup.py b/setup.py
index e5d7117..1919cea 100755
--- a/setup.py
+++ b/setup.py
@@ -135,7 +135,7 @@ def run_tests(self):
 
 setup(
     name='django-improved-user',
-    version='0.3.0',
+    version='0.4.0',
     description=(
         'A custom Django user model for best practices email-based login.'
     ),