diff --git a/types/react-big-calendar/index.d.ts b/types/react-big-calendar/index.d.ts
index eba901bfc9..e7faf76ff4 100644
--- a/types/react-big-calendar/index.d.ts
+++ b/types/react-big-calendar/index.d.ts
@@ -6,7 +6,7 @@
 //                 Sebastian Silbermann <https://github.com/eps1lon>
 //                 Paul Potsides <https://github.com/strongpauly>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
-// TypeScript Version: 2.8
+// TypeScript Version: 2.9
 import { Validator } from 'prop-types';
 import * as React from 'react';