diff --git a/package.json b/package.json
index 66b9d46..1bf381c 100644
--- a/package.json
+++ b/package.json
@@ -16,7 +16,7 @@
     "resolve": "1.1.7",
     "send": "0.16.2",
     "tunnel": "0.0.3",
-    "yargs": "12.0.1"
+    "yargs": "^15.0.2"
   },
   "devDependencies": {
     "jshint": "2.9.6",
@@ -40,5 +40,8 @@
     "test-ci": "npm run lint && npm run test-unit && npm run test-behaviour && TEST_MODE=all tests/external-tests.js",
     "test": "npm run lint && npm run test-unit && npm run test-behaviour && TEST_MODE=required tests/external-tests.js",
     "update-util": "webpack"
+  },
+  "engine": {
+    "node": ">=8"
   }
 }