diff --git a/package.json b/package.json
index a815d22a..347a483a 100644
--- a/package.json
+++ b/package.json
@@ -29,7 +29,7 @@
     "@types/sinon": "^7.0.11",
     "@types/sinon-chai": "^3.2.2",
     "chai": "^4.2.0",
-    "concurrently": "^4.1.0",
+    "concurrently": "4.1.0",
     "glob": "^7.1.3",
     "istanbul": "^0.4.5",
     "lolex": "^4.0.1",