add HKDFExpand to changelog
diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 54d6229..8a2635e 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -6,6 +6,8 @@
 
 .. note:: This version is not yet released and is under active development.
 
+* Added :class:`~cryptography.hazmat.primitives.HKDFExpand`.
+
 0.4 - 2014-05-03
 ~~~~~~~~~~~~~~~~