diff --git a/go.mod b/go.mod
index 2d40e34..9810e96 100644
--- a/go.mod
+++ b/go.mod
@@ -1,7 +1,9 @@
 // +heroku install ./...
-// +heroku goVersion go1.12
+// +heroku goVersion go1.13
 module github.com/mpolden/echoip
 
+go 1.13
+
 require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/jessevdk/go-flags v1.4.0