diff --git a/history.md b/history.md
index 66e0ad8..9db16b4 100644
--- a/history.md
+++ b/history.md
@@ -25,6 +25,9 @@ This release is largely API compatible, but makes several breaking changes.
   warning for now
 - `Response#to_i` will now behave like `String#to_i` instead of returning the
   HTTP response code, which was very surprising behavior.
+- Handle multiple HTTP response headers with the same name (except for
+  Set-Cookie, which is special) by joining the values with a comma space,
+  compliant with RFC 7230
 
 # 1.8.0