diff --git a/README.md b/README.md
index 766de0f514..6f79fd3a46 100644
--- a/README.md
+++ b/README.md
@@ -7,7 +7,7 @@ Angular.io is currently the preview site for Angular 2. This site also includes
 
 
 ## Development Setup
-1. Install [Harp](http://harpjs.com/)  
+1. Install version 0.15.2 of [Harp](http://harpjs.com/) (The latest version, 0.17, does not work with the site.)
 2. cd into root directory `angular.io/`
 3. run `harp server`
 4. Open this url in the browser: [http://localhost:9000/](http://localhost:9000/)