diff --git a/index.ts b/index.ts
index d8b76585e..0b44b11df 100644
--- a/index.ts
+++ b/index.ts
@@ -562,8 +562,7 @@ function ensureTypeScriptInstance(loaderOptions: LoaderOptions, loader: any): {
 
     // manually update changed files
     loader._compiler.plugin("watch-run", (watching, cb) => {
-        var mtimes = watching.compiler.fileTimestamps ||
-                     watching.compiler.watchFileSystem.watcher.mtimes;
+        var mtimes = watching.compiler.watchFileSystem.watcher.mtimes;
         Object.keys(mtimes)
             .filter(filePath => !!filePath.match(/\.tsx?$|\.jsx?$/))
             .forEach(filePath => {