diff --git a/History.md b/History.md
index 3623e5f..3e2ce2a 100644
--- a/History.md
+++ b/History.md
@@ -1,4 +1,13 @@
 
+0.20.0 / 2015-04-30
+==================
+
+Breaking change if you're using `this.get('ua') === undefined` etc.
+For more details please checkout [#438](https://github.com/koajs/koa/pull/438).
+
+  * make sure helpers return strict string
+  * feat: alias response.headers to response.header
+
 0.19.1 / 2015-04-14
 ==================
 
diff --git a/package.json b/package.json
index d626445..1471e70 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "koa",
-  "version": "0.19.1",
+  "version": "0.20.0",
   "description": "Koa web app framework",
   "main": "lib/application.js",
   "scripts": {