diff --git a/Changelog b/Changelog
index 20426fc0..3e57d4ab 100644
--- a/Changelog
+++ b/Changelog
@@ -4,10 +4,10 @@
  Change history
 ================
 
-.. _version-3.1.0:
+.. _version-4.0:
 
-3.1.0
-=====
+4.0
+===
 :release-date: TBA
 
 .. _version-3.0.26:
diff --git a/README.rst b/README.rst
index f005329e..9cb47bc0 100644
--- a/README.rst
+++ b/README.rst
@@ -6,7 +6,7 @@
 
 |build-status| |coverage-status|
 
-:Version: 3.1.0a1
+:Version: 4.0.0a1
 
 `Kombu` is a messaging library for Python.
 
diff --git a/kombu/__init__.py b/kombu/__init__.py
index 26e95597..6ca38e42 100644
--- a/kombu/__init__.py
+++ b/kombu/__init__.py
@@ -10,7 +10,7 @@ version_info_t = namedtuple(
     'version_info_t', ('major', 'minor', 'micro', 'releaselevel', 'serial'),
 )
 
-VERSION = version_info_t(3, 1, 0, 'a1', '')
+VERSION = version_info_t(4, 0, 0, 'a1', '')
 __version__ = '{0.major}.{0.minor}.{0.micro}{0.releaselevel}'.format(VERSION)
 __author__ = 'Ask Solem'
 __contact__ = 'ask@celeryproject.org'
@@ -20,7 +20,7 @@ __docformat__ = 'restructuredtext en'
 # -eof meta-
 
 if sys.version_info < (2, 7):  # pragma: no cover
-    raise Exception('Kombu 3.1 requires Python versions 2.7 or later.')
+    raise Exception('Kombu 4.0 requires Python versions 2.7 or later.')
 
 STATICA_HACK = True
 globals()['kcah_acitats'[::-1].upper()] = False
diff --git a/setup.py b/setup.py
index e91430ec..2e3b413a 100644
--- a/setup.py
+++ b/setup.py
@@ -11,7 +11,7 @@ extra = {}
 PY3 = sys.version_info[0] == 3
 
 if sys.version_info < (2, 7):
-    raise Exception('Kombu requires Python 2.7 or higher.')
+    raise Exception('Kombu 4.0 requires Python 2.7 or higher.')
 
 try:
     from setuptools import setup