diff --git a/types/underscore.string/index.d.ts b/types/underscore.string/index.d.ts
index eb0774b49a..ce2e46edd1 100644
--- a/types/underscore.string/index.d.ts
+++ b/types/underscore.string/index.d.ts
@@ -2,6 +2,7 @@
 // Project: https://github.com/epeli/underscore.string
 // Definitions by: Ry Racherbaumer <https://github.com/rygine>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
+// TypeScript Version: 2.1
 
 import * as _ from 'underscore';