diff --git a/package.json b/package.json
index 0a13cfc..d3b8965 100644
--- a/package.json
+++ b/package.json
@@ -37,6 +37,6 @@
     "typescript": "^2.7.1"
   },
   "dependencies": {
-    "source-map": "^0.7.0"
+    "source-map": "~0.6.1"
   }
 }