diff --git a/package.json b/package.json
index bec9c64..20afb33 100644
--- a/package.json
+++ b/package.json
@@ -11,7 +11,7 @@
     "colors": "1.x.x",
     "crontab": "1.x.x",
     "file-exists": "^2.0.0",
-    "mock-fs": "^4.0.0",
+    "mock-fs": "4.2.0",
     "username": "2.x.x",
     "yargs": "^7.0.1"
   },