diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index e0b530b2..dfafc2a4 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -1,6 +1,12 @@
 Changelog
 ---------
 
+16.4 - `master`_
+~~~~~~~~~~~~~~~~
+
+.. note:: This version is not yet released and is under active development.
+
+
 16.3 - 2016-02-21
 ~~~~~~~~~~~~~~~~~
 
@@ -127,3 +133,6 @@ Changelog
 ~~~~~~~~~~~~~~~~~
 
 * Initial release.
+
+
+.. _`master`: https://github.com/pypa/packaging/
diff --git a/packaging/__about__.py b/packaging/__about__.py
index fd84365b..b26e2979 100644
--- a/packaging/__about__.py
+++ b/packaging/__about__.py
@@ -12,7 +12,7 @@
 __summary__ = "Core utilities for Python packages"
 __uri__ = "https://github.com/pypa/packaging"
 
-__version__ = "16.3"
+__version__ = "16.4.dev0"
 
 __author__ = "Donald Stufft and individual contributors"
 __email__ = "donald@stufft.io"