diff --git a/close_go113.go b/close_go113.go
index 4f586dcb..fb226475 100644
--- a/close_go113.go
+++ b/close_go113.go
@@ -1,3 +1,4 @@
+//go:build !go1.16
 // +build !go1.16
 
 package websocket
diff --git a/close_go116.go b/close_go116.go
index 0a6e5f15..2724e0ca 100644
--- a/close_go116.go
+++ b/close_go116.go
@@ -1,3 +1,4 @@
+//go:build go1.16
 // +build go1.16
 
 package websocket