diff --git a/block-chain/package-lock.json b/block-chain/package-lock.json
index 8ca4fcd..3087b37 100644
--- a/block-chain/package-lock.json
+++ b/block-chain/package-lock.json
@@ -18,11 +18,6 @@
       "resolved": "https://registry.npmjs.org/array-flatten/-/array-flatten-1.1.1.tgz",
       "integrity": "sha1-ml9pkFGx5wczKPKgCJaLZOopVdI="
     },
-    "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=="
-    },
     "body-parser": {
       "version": "1.18.3",
       "resolved": "https://registry.npmjs.org/body-parser/-/body-parser-1.18.3.tgz",
@@ -430,12 +425,9 @@
       "integrity": "sha1-IpnwLG3tMNSllhsLn3RSShj2NPw="
     },
     "ws": {
-      "version": "6.0.0",
-      "resolved": "https://registry.npmjs.org/ws/-/ws-6.0.0.tgz",
-      "integrity": "sha512-c2UlYcAZp1VS8AORtpq6y4RJIkJ9dQz18W32SpR/qXGfLDZ2jU4y4wKvvZwqbi7U6gxFQTeE+urMbXU/tsDy4w==",
-      "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/block-chain/package.json b/block-chain/package.json
index e831ac1..feb55ea 100644
--- a/block-chain/package.json
+++ b/block-chain/package.json
@@ -12,6 +12,6 @@
     "body-parser": "^1.18.3",
     "crypto-js": "^3.1.9-1",
     "express": "^4.16.3",
-    "ws": "^6.0.0"
+    "ws": "^7.4.6"
   }
 }