diff --git a/.travis.yml b/.travis.yml
index bef0db7..b051af3 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,14 +1,12 @@
 language: go
 
 go:
-  - "1.9"
-  - "1.10"
-  - "1.11"
-  - "1.12"
-  - "tip"
+  - 1.11.x
+  - 1.12.x
+  - tip
 
 before_script:
-  - go vet ./...
+  - go -all vet ./...
 
 script:
   - ./go.test.sh
diff --git a/go.mod b/go.mod
index c42c5a9..a63a33a 100644
--- a/go.mod
+++ b/go.mod
@@ -1 +1,3 @@
 module github.com/gammazero/deque
+
+go 1.12