diff --git a/functions/router/index.js b/functions/router/index.js
new file mode 100644
index 00000000..54f4f7a2
--- /dev/null
+++ b/functions/router/index.js
@@ -0,0 +1,28 @@
+export default async function(req) {
+  const url = new URL(req.url);
+  const path = url.pathname;
+
+  // Determine version from path
+  let version = 'latest';
+  if (path.startsWith('/v/')) {
+    const match = path.match(/^\/v\/([^\/]+)/);
+    if (match) version = match[1];
+  }
+
+  // For HTML navigation (no file extension), serve index.html
+  if (!path.match(/\.[a-z]+$/i)) {
+    const htmlUrl = `https://${url.host}/v/${version}/index.html`;
+    const response = await fetch(htmlUrl);
+    return new Response(response.body, {
+      headers: {
+        'Content-Type': 'text/html',
+        'Cache-Control': 'no-cache'
+      }
+    });
+  }
+
+  // For assets, pass through
+  const assetUrl = `https://${url.host}${path}`;
+  return fetch(assetUrl);
+}
+
diff --git a/functions/router/package.json b/functions/router/package.json
new file mode 100644
index 00000000..a2a59768
--- /dev/null
+++ b/functions/router/package.json
@@ -0,0 +1,6 @@
+{
+  "name": "router",
+  "version": "1.0.0",
+  "main": "index.js"
+}
+
diff --git a/ui/build-all.sh b/ui/build-all.sh
new file mode 100755
index 00000000..1ed908c8
--- /dev/null
+++ b/ui/build-all.sh
@@ -0,0 +1,23 @@
+#!/bin/bash
+set -e
+
+# Build latest (includes device list)
+echo "Building latest..."
+VITE_BASE_PATH=/v/latest/ npm run build:prod -- --outDir dist-temp
+mkdir -p dist/v/latest
+cp -r dist-temp/* dist/v/latest/
+
+# Build for each firmware version you support
+echo "Building v2025.11.07..."
+VITE_BASE_PATH=/v/2025.11.07/ npm run build:prod -- --outDir dist-temp
+mkdir -p dist/v/2025.11.07
+cp -r dist-temp/* dist/v/2025.11.07/
+
+echo "Building v2025.10.15..."
+VITE_BASE_PATH=/v/2025.10.15/ npm run build:prod -- --outDir dist-temp
+mkdir -p dist/v/2025.10.15
+cp -r dist-temp/* dist/v/2025.10.15/
+
+rm -rf dist-temp
+echo "✓ All versions built to dist/v/"
+
diff --git a/ui/package.json b/ui/package.json
index 70eaa662..f56ff63a 100644
--- a/ui/package.json
+++ b/ui/package.json
@@ -4,13 +4,14 @@
   "version": "2025.11.07.2130",
   "type": "module",
   "engines": {
-    "node": "^22.20.0"
+    "node": "22.x"
   },
   "scripts": {
     "dev": "./dev_device.sh",
     "dev:ssl": "USE_SSL=true ./dev_device.sh",
     "dev:cloud": "vite dev --mode=cloud-development",
     "build": "npm run build:prod",
+    "build:all": "./build-all.sh",
     "build:device": "npm run i18n:compile && tsc && vite build --mode=device --emptyOutDir",
     "build:staging": "npm run i18n:compile && tsc && vite build --mode=cloud-staging",
     "build:prod": "npm run i18n:compile && tsc && vite build --mode=cloud-production",