diff --git a/README.md b/README.md
index 93dbc56..f93b12a 100644
--- a/README.md
+++ b/README.md
@@ -10,6 +10,7 @@ A surgical debugging tool to uncover the layers under your app.
 Usage
 -----
 
+**NOTE**: This library is avaliable only for API 9 and above.
 Place a `ScalpelFrameLayout` at the root of your hierarchy.
 
  * Enable the 3D interaction with `setLayerInteractionEnabled(boolean)`.