diff --git a/chap04/package-lock.json b/chap04/package-lock.json
index 2b3d57b..bc39588 100644
--- a/chap04/package-lock.json
+++ b/chap04/package-lock.json
@@ -4,11 +4,6 @@
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
-    "async-limiter": {
-      "version": "1.0.0",
-      "resolved": "https://registry.npmjs.org/async-limiter/-/async-limiter-1.0.0.tgz",
-      "integrity": "sha512-jp/uFnooOiO+L211eZOoSyzpOITMXx1rBITauYykG3BRYPu8h0UcxsPNB04RR5vo4Tyz3+ay17tR6JVf9qzYWg=="
-    },
     "fs": {
       "version": "0.0.1-security",
       "resolved": "https://registry.npmjs.org/fs/-/fs-0.0.1-security.tgz",
@@ -20,12 +15,9 @@
       "integrity": "sha1-PDfHrhqO65ZpBKKtHpdaGUt+06Q="
     },
     "ws": {
-      "version": "6.1.0",
-      "resolved": "https://registry.npmjs.org/ws/-/ws-6.1.0.tgz",
-      "integrity": "sha512-H3dGVdGvW2H8bnYpIDc3u3LH8Wue3Qh+Zto6aXXFzvESkTVT6rAfKR6tR/+coaUvxs8yHtmNV0uioBF62ZGSTg==",
-      "requires": {
-        "async-limiter": "~1.0.0"
-      }
+      "version": "7.4.6",
+      "resolved": "https://registry.npmjs.org/ws/-/ws-7.4.6.tgz",
+      "integrity": "sha512-YmhHDO4MzaDLB+M9ym/mDA5z0naX8j7SIlT8f8z+I0VtzsRbekxEutHSme7NPS2qE8StCYQNUnfWdXta/Yu85A=="
     }
   }
 }
diff --git a/chap04/package.json b/chap04/package.json
index 46eebae..ceadff0 100644
--- a/chap04/package.json
+++ b/chap04/package.json
@@ -14,6 +14,6 @@
   "dependencies": {
     "fs": "0.0.1-security",
     "https": "^1.0.0",
-    "ws": "^6.1.0"
+    "ws": "^7.4.6"
   }
 }