Update changelog

Change-Id: I5938b9b13023cc856f53691ad247f057142fb9de
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 77a1ad9..d2385fc 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,10 @@
 # Changelog
 
+## 2.2.4
+
+* minor code cleanups
+* some API documentation added
+
 ## 2.2.3
 
 * Updated dependencies