diff --git a/web/index.html b/web/index.html
index 5a28fe33..0cab0618 100644
--- a/web/index.html
+++ b/web/index.html
@@ -291,6 +291,9 @@
 <a id="invisible_click" href="javascript:;" onclick="Main.clickNav()"></a>
 
 <script type="text/javascript">
+	if ('serviceWorker' in navigator) {
+		navigator.serviceWorker.register('./sw.js');
+	}
 	var canvas = document.getElementById('canvas');
 
 	var Module = {};
diff --git a/web/main.js b/web/main.js
index 0710d0da..e77901f1 100644
--- a/web/main.js
+++ b/web/main.js
@@ -280,10 +280,3 @@ window.addEventListener("drop", function(e) {
   Main.dragDrop(e);
   document.body.style["opacity"] = 1.0;
 }, false);
-
-window.onload = function() {
-  'use strict';
-  if ('serviceWorker' in navigator) {
-    navigator.serviceWorker.register('sw.js');
-  }
-}
diff --git a/web/pwa.json b/web/pwa.json
index b1525116..f7dadd42 100644
--- a/web/pwa.json
+++ b/web/pwa.json
@@ -3,10 +3,11 @@
 	"dir": "ltr",
 	"name": "Cimbar Encoder",
 	"short_name": "cimbar.org",
-	"icons": [],
+	"icons": [{"src":"/android-chrome-192x192.png","sizes":"192x192","type":"image/png"},{"src":"/android-chrome-512x512.png","sizes":"512x512","type":"image/png"}],
 	"scope": "/",
 	"start_url": "/index.html",
 	"display": "fullscreen",
 	"theme_color": "aliceblue",
 	"background_color": "black"
 }
+
diff --git a/web/sw.js b/web/sw.js
index b52ef617..b9ab0e73 100644
--- a/web/sw.js
+++ b/web/sw.js
@@ -1,7 +1,6 @@
 
-var _cacheName = 'cimbar-js-pwa';
+var _cacheName = 'cimbar-js-v0.5.8';
 var _cacheFiles = [
-  '/',
   '/index.html',
   '/cimbar_js.js',
   '/cimbar_js.wasm',
@@ -26,3 +25,15 @@ self.addEventListener('fetch', function(e) {
     })
   );
 });
+
+// clean old caches
+self.addEventListener('activate', function(e) {
+  e.waitUntil(caches.keys().then(function(keyList) {
+    Promise.all(keyList.map(function(key) {
+      if (key === _cacheName) {
+        return;
+      }
+      caches.delete(key);
+    }));
+  })());
+});