Update README.md

Author: jimaobian

README.md

@@ -1,4 +1,7 @@
 # DFPlayer - A Mini MP3 Player For Arduino
+
+**THIS LIBRARY IS NOT COMPATIBLE WITH ARDUINO.ORG. PLEASE USE THE IDE FROM ARDUINO.CC**
+
 DFPlayer - A Mini MP3 Player For Arduino
 
 https://www.dfrobot.com/index.php?route=product/product&product_id=1121
@@ -17,4 +20,4 @@ Notice and Trouble shooting
 1.Connection and Diagram can be found here
 https://www.dfrobot.com/wiki/index.php/DFPlayer_Mini_SKU:DFR0299#Connection_Diagram
 
-2.This code is tested on Arduino Uno, Leonardo, Mega boards.
+2.This code is tested on Arduino Uno, Leonardo, Mega boards.