// You will probably need to tell the service worker to check the server for updates, I usually use a service for this:

export class UpdateService {

  constructor(public updates: SwUpdate) {
    if (updates.isEnabled) {
      interval(6 * 60 * 60).subscribe(() => updates.checkForUpdate()
        .then(() => console.log('checking for updates')));
    }
  }

  public checkForUpdates(): void {
    this.updates.available.subscribe(event => this.promptUser());
  }

  private promptUser(): void {
    console.log('updating to new version');
    this.updates.activateUpdate().then(() => document.location.reload()); 
  }
// In your app-component.ts:

  constructor(private sw: UpdateService) {
    // check the service worker for updates
    this.sw.checkForUpdates();
  }
// For whatever reason, Angular sometimes does not register the service worker properly. So you can modify `main.ts` :
// Replace:

// platformBrowserDynamic().bootstrapModule(AppModule);
// With:

platformBrowserDynamic().bootstrapModule(AppModule).then(() => {
  if ('serviceWorker' in navigator && environment.production) {
    navigator.serviceWorker.register('ngsw-worker.js');
  }
}).catch(err => console.log(err));