diff --git a/README.md b/README.md
index 3d48d41..a6467b1 100644
--- a/README.md
+++ b/README.md
@@ -173,7 +173,9 @@ Restores a previously purchased IAP to the user (for example if they have upgrad
  will fail silently.
 
 
+#### Important Note
 
+In order for this library to work correctly, you must provide your, `app.identifier` to the Rakefile. 
 
 
 Find the Product ID here: