Update README.md

Author: geof90

README.md

@@ -240,6 +240,8 @@ And that's it for installation using RNPM! Continue below to the [Plugin Configu
 
 ### Plugin Configuration (Android)
 
+*Note: If you are using an older version (<= 1.9.0-beta) of the CodePush plugin, please refer to [these docs](https://github.com/Microsoft/react-native-code-push/tree/e717eb024fe9d1810ac21c40c097f7bc165ea5f1#plugin-configuration-android---react-native--v0180) instead.
+
 After installing the plugin and syncing your Android Studio project with Gradle, you need to configure your app to consult CodePush for the location of your JS bundle, since it will "take control" of managing the current and all future versions. To do this, update the `MainActivity.java` file to use CodePush via the following changes:
 
 ```java