diff --git a/internal/genv/main.go b/internal/genv/main.go
index 37e035d..dd19223 100644
--- a/internal/genv/main.go
+++ b/internal/genv/main.go
@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build go1.13
 // +build go1.13
 
 // The genv command generates version-specific go command source files.
diff --git a/internal/genv/main_test.go b/internal/genv/main_test.go
index ecffed2..6b25e91 100644
--- a/internal/genv/main_test.go
+++ b/internal/genv/main_test.go
@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build go1.13
 // +build go1.13
 
 package main