diff --git a/src/main/service.js b/src/main/service.js
index ba1f7104..f323d9d9 100644
--- a/src/main/service.js
+++ b/src/main/service.js
@@ -1,5 +1,7 @@
+const service_worker = navigator.serviceWorker;
+
 async function start_service_worker() {
-    const version = 62;
+    const version = 64;
     function debug() {
         console.log(`[${version}]`, ...arguments);
     }
@@ -19,9 +21,13 @@ async function start_service_worker() {
         } else {
             debug({ service_worker: reg });
         }
-        navigator.serviceWorker.controller.postMessage('ctrl message');
+
+        if (service_worker.controller) {
+            service_worker.controller.postMessage('ctrl message');
+        }
     } catch (err) {
-        debug('service worker registration failed');
+        debug('service worker registration failed', err);
     }
 }
-if (navigator.serviceWorker) start_service_worker();
+
+if (service_worker) start_service_worker();
diff --git a/src/moto/service.js b/src/moto/service.js
index 63e67fd1..eeb97a12 100644
--- a/src/moto/service.js
+++ b/src/moto/service.js
@@ -1,4 +1,4 @@
-const version = 62;
+const version = 64;
 const stats = {
     hit: 0,
     miss: 0,
diff --git a/web/kiri/index.html b/web/kiri/index.html
index c09ccaea..8711f113 100644
--- a/web/kiri/index.html
+++ b/web/kiri/index.html
@@ -19,7 +19,8 @@
     <link rel="apple-touch-icon" href="/kiri/favicon-mobile.png">
     <link rel="stylesheet" type="text/css" href="/kiri/index.css?{{version}}">
     <link href="/font/css/all.min.css" rel="stylesheet">
-    <script src="/code/cache.js?62" defer></script>
+    <link href="/kiri/manifest.json" rel="manifest">
+    <script src="/code/cache.js?64" defer></script>
     <script src="/font/js/all.min.js" crossorigin="anonymous" defer></script>
     <script src="/code/kiri.js?{{version}}"></script>
 </head>