diff --git a/messages_types_v5.go b/messages_types_v5.go
index 2b1c981..9213908 100644
--- a/messages_types_v5.go
+++ b/messages_types_v5.go
@@ -1,6 +1,7 @@
 package mailgun
 
 // This file contains a draft for new v5 messages.
+// TODO(v5): remove this file
 
 import (
 	"io"
diff --git a/messages_v5.go b/messages_v5.go
index cbd0c4f..4342ed7 100644
--- a/messages_v5.go
+++ b/messages_v5.go
@@ -1,6 +1,7 @@
 package mailgun
 
 // This file contains methods for new v5 messages.
+// TODO(v5): remove this file
 
 import (
 	"context"