diff --git a/package-lock.json b/package-lock.json
index 6b1413b..5c2e6ab 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -6,7 +6,7 @@
     "": {
       "name": "cesium-helpers",
       "devDependencies": {
-        "@cesium/engine": "20.0.1",
+        "@cesium/engine": "21.0.1",
         "gh-pages": "6.3.0",
         "lerna": "8.2.4",
         "lit": "3.3.1",
@@ -39,16 +39,16 @@
       }
     },
     "node_modules/@cesium/engine": {
-      "version": "20.0.1",
-      "resolved": "https://registry.npmjs.org/@cesium/engine/-/engine-20.0.1.tgz",
-      "integrity": "sha512-B2TQ9VtVb791dUJatgx6SCRZg3tFPcRi8QseWg9flovaFOHJY0o+LX5BN2J5plFKRO5r5v7g+M2OyjcUYwaRDQ==",
+      "version": "21.0.1",
+      "resolved": "https://registry.npmjs.org/@cesium/engine/-/engine-21.0.1.tgz",
+      "integrity": "sha512-V4MEHOcYMcg+zCxrPjPAVpUyJxmIw6K9qPz5Fd2fnYPoMSPV7FJsiZYoFns03yoPHOPIeqnXQNspZKLX5Xzgfw==",
       "dev": true,
       "license": "Apache-2.0",
       "dependencies": {
         "@cesium/wasm-splats": "^0.1.0-alpha.2",
         "@spz-loader/core": "0.3.0",
         "@tweenjs/tween.js": "^25.0.0",
-        "@zip.js/zip.js": "^2.7.70 <2.8.0",
+        "@zip.js/zip.js": "^2.8.1",
         "autolinker": "^4.0.0",
         "bitmap-sdf": "^1.0.3",
         "dompurify": "^3.0.2",
@@ -3649,15 +3649,15 @@
       "license": "BSD-3-Clause"
     },
     "node_modules/@zip.js/zip.js": {
-      "version": "2.7.72",
-      "resolved": "https://registry.npmjs.org/@zip.js/zip.js/-/zip.js-2.7.72.tgz",
-      "integrity": "sha512-3/A4JwrgkvGBlCxtItjxs8HrNbuTAAl/zlGkV6tC5Fb5k5nk4x2Dqxwl/YnUys5Ch+QB01eJ8Q5K/J2uXfy9Vw==",
+      "version": "2.8.8",
+      "resolved": "https://registry.npmjs.org/@zip.js/zip.js/-/zip.js-2.8.8.tgz",
+      "integrity": "sha512-v0KutehhSAuaoFAFGLp+V4+UiZ1mIxQ8vNOYMD7k9ZJaBbtQV49MYlg568oRLiuwWDg2Di58Iw3Q0ESNWR+5JA==",
       "dev": true,
       "license": "BSD-3-Clause",
       "engines": {
         "bun": ">=0.7.0",
         "deno": ">=1.0.0",
-        "node": ">=16.5.0"
+        "node": ">=18.0.0"
       }
     },
     "node_modules/@zkochan/js-yaml": {
diff --git a/package.json b/package.json
index d4d5450..5f9e701 100644
--- a/package.json
+++ b/package.json
@@ -14,7 +14,7 @@
     "gh-pages": "rm -rf dist && npm run build-demos && gh-pages -d dist"
   },
   "devDependencies": {
-    "@cesium/engine": "20.0.1",
+    "@cesium/engine": "21.0.1",
     "gh-pages": "6.3.0",
     "lerna": "8.2.4",
     "lit": "3.3.1",