diff --git a/js/pacosako_ui.js b/js/pacosako_ui.js
index d9bf8f1..4730948 100644
--- a/js/pacosako_ui.js
+++ b/js/pacosako_ui.js
@@ -18,6 +18,8 @@ import escape from 'lodash/escape';
 import jBox from 'jbox';
 import 'jbox/dist/jBox.all.css';
 
+import {Workbox, messageSW} from 'workbox-window';
+
 /* "Waterdrop" by Porphyr (freesound.org/people/Porphyr) / CC BY 3.0 (creativecommons.org/licenses/by/3.0) */
 import Waterdrop from '../wav/191678__porphyr__waterdrop.wav';
 
@@ -803,14 +805,68 @@ $(function (){
       }
    }
 
-   try {
-      navigator.serviceWorker.register('sw.js').catch(disableNotify);
+   if ('serviceWorker' in navigator) {
+      let confirmBox = null;
 
-      if (Notification.permission === 'denied') {
+      Promise.resolve().then(async () => {
+         const wb = new Workbox('sw.js');
+
+         function showSkipWaitingPrompt(event) {
+            if (confirmBox) {
+               confirmBox.close({ ignoreDelay: true });
+            }
+
+            confirmBox = new jBox('Confirm', {
+               attach: null,
+               content: "A new version is available. Update the page?",
+               confirmButton: `<span class="update-confirm-button">Update</span>`,
+               cancelButton: 'Not now',
+               closeOnConfirm: false,
+               confirm() {
+                  /* The SW should signal us to reload, but do it after 20s regardless. */
+                  setTimeout(() => { window.location.reload(); }, 20000);
+                  messageSW(event.sw, {type: 'SKIP_WAITING'});
+                  $('.update-confirm-button').text('Updating…');
+               },
+               onCloseComplete() {
+                  this.destroy();
+               },
+            });
+
+            confirmBox.open();
+         }
+
+         wb.addEventListener('installed', (event) => {
+            try {
+               if (Notification.permission === 'denied') {
+                  disableNotify();
+               }
+            } catch (err) {
+               disableNotify();
+            }
+         });
+
+         wb.addEventListener('controlling', (event) => {
+            if (event.isUpdate) {
+               window.location.reload();
+            }
+         });
+
+         wb.addEventListener('waiting', showSkipWaitingPrompt);
+         wb.addEventListener('externalwaiting', showSkipWaitingPrompt);
+
+         const registration = await wb.register();
+
+         if ('update' in registration) {
+            /* Check for updates every 4h without reloading the page. */
+            setInterval(() => { registration.update(); }, 4*3600*1000);
+         } else {
+            console.log('service worker update method not supported, disabling update checks');
+         }
+      }).catch((err) => {
+         console.error('failed to register the service worker', err);
          disableNotify();
-      }
-   } catch (err) {
-      disableNotify();
+      });
    }
 
    const LS_KEY_NOTIFY = 'pacosako/notify';
@@ -1166,9 +1222,6 @@ $(function (){
       }
    };
 
-   /* force page reload after four hours to keep client code up to date */
-   window.setTimeout(function(){ location.reload(); }, 4*3600*1000);
-
    const foundId = location.hash.match(/^#\/([0-9a-f]{16}\b)/);
    if (foundId) {
       switchGameId(foundId[1]);
diff --git a/package-lock.json b/package-lock.json
index a7274bd..be98029 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,6 +1,6 @@
 {
   "name": "paco_sako",
-  "version": "0.2.0",
+  "version": "0.4.0",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
diff --git a/package.json b/package.json
index 0ed8768..300f57c 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "paco_sako",
-  "version": "0.3.0",
+  "version": "0.4.0",
   "description": "Online version of the Paco Ŝako chess variation",
   "browser": "index.js",
   "scripts": {
@@ -33,7 +33,8 @@
     "workbox-precaching": "^5.1.3",
     "workbox-routing": "^5.1.3",
     "workbox-strategies": "^5.1.3",
-    "workbox-webpack-plugin": "^5.1.3"
+    "workbox-webpack-plugin": "^5.1.3",
+    "workbox-window": "^5.1.3"
   },
   "dependencies": {}
 }
diff --git a/sw.js b/sw.js
index f42288d..9303307 100644
--- a/sw.js
+++ b/sw.js
@@ -8,3 +8,9 @@ registerRoute(
    new RegExp('^https://fonts\\.googleapis\\.com/|https://fonts\\.gstatic\\.com/'),
    new StaleWhileRevalidate()
 );
+
+addEventListener('message', (event) => {
+   if (event.data && event.data.type === 'SKIP_WAITING') {
+      skipWaiting();
+   }
+});