diff --git a/mongoose/index.d.ts b/mongoose/index.d.ts
index 0ede2141a8..2c7361a437 100644
--- a/mongoose/index.d.ts
+++ b/mongoose/index.d.ts
@@ -2,6 +2,7 @@
 // Project: http://mongoosejs.com/
 // Definitions by: simonxca <https://github.com/simonxca/>, horiuchi <https://github.com/horiuchi/>, sindrenm <https://github.com/sindrenm>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
+// TypeScript Version: 2.1
 
 /// <reference types="mongodb" />
 /// <reference types="node" />