diff --git a/go.mod b/go.mod
index aaaf57e..4544601 100644
--- a/go.mod
+++ b/go.mod
@@ -1,6 +1,6 @@
 module github.com/robinson/gos7
 
-go 1.23
+go 1.21.1
 
 require github.com/tarm/serial v0.0.0-20180830185346-98f6abe2eb07