diff --git a/reference-implementation/package-lock.json b/reference-implementation/package-lock.json
index ffc90a4..cac73b0 100644
--- a/reference-implementation/package-lock.json
+++ b/reference-implementation/package-lock.json
@@ -2455,15 +2455,24 @@
       "dev": true
     },
     "handlebars": {
-      "version": "4.1.2",
-      "resolved": "https://registry.npmjs.org/handlebars/-/handlebars-4.1.2.tgz",
-      "integrity": "sha512-nvfrjqvt9xQ8Z/w0ijewdD/vvWDTOweBUm96NTr66Wfvo1mJenBLwcYmPs3TIBP5ruzYGD7Hx/DaM9RmhroGPw==",
+      "version": "4.7.6",
+      "resolved": "https://registry.npmjs.org/handlebars/-/handlebars-4.7.6.tgz",
+      "integrity": "sha512-1f2BACcBfiwAfStCKZNrUCgqNZkGsAT7UM3kkYtXuLo0KnaVfjKOyf7PRzB6++aK9STyT1Pd2ZCPe3EGOXleXA==",
       "dev": true,
       "requires": {
+        "minimist": "^1.2.5",
         "neo-async": "^2.6.0",
-        "optimist": "^0.6.1",
         "source-map": "^0.6.1",
-        "uglify-js": "^3.1.4"
+        "uglify-js": "^3.1.4",
+        "wordwrap": "^1.0.0"
+      },
+      "dependencies": {
+        "minimist": {
+          "version": "1.2.5",
+          "resolved": "https://registry.npmjs.org/minimist/-/minimist-1.2.5.tgz",
+          "integrity": "sha512-FM9nNUYrRBAELZQT3xeZQ7fmMOBg6nWNmJKTcgsJeaLstP/UODVpGsr5OhXhhXg6f+qtJ8uiZ+PUxkDWcgIXLw==",
+          "dev": true
+        }
       }
     },
     "har-schema": {
@@ -3689,7 +3698,7 @@
     },
     "minimist": {
       "version": "0.0.8",
-      "resolved": "http://registry.npmjs.org/minimist/-/minimist-0.0.8.tgz",
+      "resolved": "https://registry.npmjs.org/minimist/-/minimist-0.0.8.tgz",
       "integrity": "sha1-hX/Kv8M5fSYluCKCYuhqp6ARsF0=",
       "dev": true
     },
@@ -3929,24 +3938,6 @@
         "mimic-fn": "^1.0.0"
       }
     },
-    "optimist": {
-      "version": "0.6.1",
-      "resolved": "https://registry.npmjs.org/optimist/-/optimist-0.6.1.tgz",
-      "integrity": "sha1-2j6nRob6IaGaERwybpDrFaAZZoY=",
-      "dev": true,
-      "requires": {
-        "minimist": "~0.0.1",
-        "wordwrap": "~0.0.2"
-      },
-      "dependencies": {
-        "wordwrap": {
-          "version": "0.0.3",
-          "resolved": "https://registry.npmjs.org/wordwrap/-/wordwrap-0.0.3.tgz",
-          "integrity": "sha1-o9XabNXAvAAI03I0u68b7WMFkQc=",
-          "dev": true
-        }
-      }
-    },
     "optionator": {
       "version": "0.8.2",
       "resolved": "https://registry.npmjs.org/optionator/-/optionator-0.8.2.tgz",
@@ -4463,7 +4454,7 @@
       "dependencies": {
         "minimist": {
           "version": "1.2.0",
-          "resolved": "http://registry.npmjs.org/minimist/-/minimist-1.2.0.tgz",
+          "resolved": "https://registry.npmjs.org/minimist/-/minimist-1.2.0.tgz",
           "integrity": "sha1-o1AIsg9BOD7sH7kU9M1d95omQoQ=",
           "dev": true
         }