diff --git a/package-lock.json b/package-lock.json
index 4972e280..e699e6cb 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -20,7 +20,7 @@
         "@cablanchard/tsconfig": "~2.0.0",
         "@ideal-postcodes/api-fixtures": "~1.2.0",
         "@ideal-postcodes/api-typings": "~2.1.0",
-        "@ideal-postcodes/jsutil": "~4.6.0",
+        "@ideal-postcodes/jsutil": "~6.4.0",
         "@prettier/plugin-php": "~0.18.4",
         "@prettier/plugin-xml": "~0.13.1",
         "@rollup/plugin-commonjs": "~21.0.2",
@@ -10413,9 +10413,10 @@
       }
     },
     "node_modules/@ideal-postcodes/jsutil": {
-      "version": "4.6.0",
-      "resolved": "https://registry.npmjs.org/@ideal-postcodes/jsutil/-/jsutil-4.6.0.tgz",
-      "integrity": "sha512-VbW2oinSdYh0HjSua7yJLX9wNysRuJzIk6x0v0Pgk+eeXCLsVXnnjiOp7XzMQ+7iH7TprW+dSmft4DwEhgRRow==",
+      "version": "6.4.0",
+      "resolved": "https://registry.npmjs.org/@ideal-postcodes/jsutil/-/jsutil-6.4.0.tgz",
+      "integrity": "sha512-r23/Ynd7guivi/UJAJ4Tvgnjnq9X++EfboUqwVBFg9e3WsBMl4PAdSf+68X6LM359ydL6cDGltjzZ9vm/lh13A==",
+      "dev": true,
       "dependencies": {
         "capitalise-post-town": "~3.0.1"
       },
@@ -10471,6 +10472,17 @@
         "node": ">=8.0"
       }
     },
+    "node_modules/@ideal-postcodes/postcode-lookup/node_modules/@ideal-postcodes/jsutil": {
+      "version": "4.6.1",
+      "resolved": "https://registry.npmjs.org/@ideal-postcodes/jsutil/-/jsutil-4.6.1.tgz",
+      "integrity": "sha512-AUTVNQJIUFYzuo/uupP8/soXFBv7NIWJaAQHipf9/00MpuLLeWxzQWxlM/t0lDReKUB6BYpIq0BBYFOVuMQDJA==",
+      "dependencies": {
+        "capitalise-post-town": "~3.0.1"
+      },
+      "engines": {
+        "node": ">=10.0"
+      }
+    },
     "node_modules/@mdn/browser-compat-data": {
       "version": "3.3.14",
       "resolved": "https://registry.npmjs.org/@mdn/browser-compat-data/-/browser-compat-data-3.3.14.tgz",
diff --git a/package.json b/package.json
index d58d3a96..a0bdb5d2 100644
--- a/package.json
+++ b/package.json
@@ -49,7 +49,7 @@
     "@cablanchard/tsconfig": "~2.0.0",
     "@ideal-postcodes/api-fixtures": "~1.2.0",
     "@ideal-postcodes/api-typings": "~2.1.0",
-    "@ideal-postcodes/jsutil": "~4.6.0",
+    "@ideal-postcodes/jsutil": "~6.4.0",
     "@prettier/plugin-php": "~0.18.4",
     "@prettier/plugin-xml": "~0.13.1",
     "@rollup/plugin-commonjs": "~21.0.2",