diff --git a/wled00/wled00.cpp b/wled00/wled00.cpp
index 866543ab9..f3f090715 100644
--- a/wled00/wled00.cpp
+++ b/wled00/wled00.cpp
@@ -1,9 +1,12 @@
+#include <Arduino.h>
 /*
  * WLED Arduino IDE compatibility file.
+ * (this is the former wled00.ino)
  * 
  * Where has everything gone?
  * 
- * In April 2020, the project's structure underwent a major change. 
+ * In April 2020, the project's structure underwent a major change.
+ * We now use the platformIO build system, and building WLED in Arduino IDE is not supported any more.
  * Global variables are now found in file "wled.h"
  * Global function declarations are found in "fcn_declare.h"
  *