diff --git a/docs/Installation.md b/docs/Installation.md
index f5d8529b..73aefdbd 100644
--- a/docs/Installation.md
+++ b/docs/Installation.md
@@ -33,7 +33,7 @@ regular "pi" user:
 
 ```
 virtualenv ~/klippy-env
-~/klippy-env/bin/pip install cffi==1.6.0 pyserial==2.7 greenlet==0.4.10
+~/klippy-env/bin/pip install cffi==1.6.0 pyserial==3.2.1 greenlet==0.4.10
 ```
 
 Building Klipper