Release v1.6.6 (#489)

diff --git a/CHANGELOG b/CHANGELOG
index 7264c9b..f53813c 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,12 @@
+v1.6.6
+  Version 1.6.6
+
+  Bugfix release
+
+  - Warn when constructing BatchHttpRequest using the legacy batch URI (#488)
+  - Increase the default media chunksize to 100MB. (#482)
+  - Remove unnecessary parsing of mime headers in HttpRequest.__init__ (#467)
+
 v1.6.5
   Version 1.6.5