title: Service Worker: files are updated on the server but old version showing in browser
body: <p>I am building a static app with PouchDB on Google AppEngine.</p>
  
  <p><strong>When I open the site in a browser window, it is showing a version I uploaded several hours ago.</strong></p>
  
  <p><strong>If I open the site in an incognito window, the updated version is displayed (therefore I don't think it is actually an error in the console).</strong></p>
  
  <p>I put a new version number in <code>app.yaml</code></p>
  
  <p>I have migrated all traffic to the new version.</p>
  
  <p>I have cleared my cache, deleted cookies, checked my application data, everything. I even reinstalled Chrome and Firefox.</p>
  
  <p>I updated my Python version and my Google AppEngine Launcher yesterday; the problem pre-dated that update.</p>
  
  <p>Also: just discovered that if I go to the URL of the updated version 
  <code>http://4.[app-id].appspot.com</code>, it displays the correct, updated version.</p>
  
  <p>This is happening in Chrome, Firefox, and Edge.</p>
  
  <p>Edit: probably should have mentioned that my site uses Service Workers and IndexedDB. I assume my service workers are caching the previous version, but I would have thought that <code>Ctrl + F5</code> would clear the cache and show the new version.</p>