diff --git a/Trinket_Ultrasonic_Rangefinder/README.md b/Trinket_Ultrasonic_Rangefinder/README.md
index 20329235f..d143627ba 100644
--- a/Trinket_Ultrasonic_Rangefinder/README.md
+++ b/Trinket_Ultrasonic_Rangefinder/README.md
@@ -2,3 +2,5 @@
 
 Code to accompany this tutorial:
 https://learn.adafruit.com/trinket-ultrasonic-rangefinder
+
+Currently limited to M0 versions due to an issue in the Arduino IDE