diff --git a/.travis.yml b/.travis.yml
index c29939f..4f4e0af 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,9 +1,5 @@
 sudo: false
 language: go
 go:
-  - 1.5.x
-  - 1.6.x
-  - 1.7.x
-  - 1.8.x
-  - 1.9.x
+  - 1.16.x
   - tip
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..94ec8ec
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,3 @@
+module github.com/mattevans/postmark-go
+
+go 1.16