If you know that certain update is available of your already downloaded app on your Windows Phone, these steps will explain how you can force an update.

  1. Go to the Store (formerly Marketplace) on your Windows Phone.
  2. Search for the app that you know has an update available.
  3. Tap on this app to see its product page.
  4. You probably only get the option to Share this app at this moment.
  5. Tap the back key.
  6. Tap one more time on the app in that search result.
  7. Now you should get an update button right next to the Share button as well.
  8. Tap on the Update and your are one step ahead of your Store notification tile.