diff --git a/readme.txt b/readme.txt
index a3084fb..f50c30b 100644
--- a/readme.txt
+++ b/readme.txt
@@ -15,6 +15,11 @@ For python2:
 
   sudo pip install paho-mqtt
 
+If running python3 on Debian based system,
+and weewx is not running in a separate python environment:
+
+  sudo apt-get install python3-paho-mqtt
+
 ===============================================================================
 Installation instructions: