diff --git a/README.md b/README.md
index c030488c..0a64efb0 100644
--- a/README.md
+++ b/README.md
@@ -5,6 +5,8 @@ To test out SSTV:
 mkdir ~/sstv
 wget -O ~/sstv/sstv.wav "https://drive.google.com/uc?export=download&id=1nCJsH2Adm0pqgg2hEYzG4YYgmfBr4lxx"
 
+update pi-power-button to latest dev branch.
+
 edit .mode to ARG1=s or use push button and release on 4 flashes.
 
 The CubeSat Simulator https://github.com/alanbjohnston/CubeSatSim/wiki is a low cost satellite emulator that runs on solar panels and batteries, transmits UHF radio telemetry, has a 3D printed frame, and can be extended by additional sensors and modules.  This project is sponsored by the not-for-profit [Radio Amateur Satellite Corporation, AMSAT®](https://amsat.org).