If you have used a Nokia Lumia phone, you may already see how Nokia forces the users to update their apps. They put the blank page with a background image and an Update button right after the splash screen (if there is one); tapping the button will get you to the app’s detail page in Windows Phone Store and you can update the app directly there. On the developer side, to do the same thing, you just have to use the API exposed through MarketplaceDetailTask to jump to that detail page.
The situation seems to be more complicated on Windows 8 with the Windows Store. Unlike the Windows Phone Store, going to the app’s detail page in Windows Store will not show you any update buttons. Instead, you will have to go to Settings charm of the Store, choose App updates and tap on Check for updates. How to do all these steps programmatically from your app (to help your users to quickly update the app)?
I had thought about showing a screen with screenshots telling people to do all the above steps by themselves, but it seemed to be too troublesome for the users. Then I saw an ads on Bing Sport app showing that there was an update in the Store, tapping on the ads jumped us directly to the Check for updates page, which is so nice and convenient! Therefore, I realized the Windows Store must already handle some special kinds of protocols or URL formats for that, and after some times trying, I figured out the magic words:
ms-windows-store:updates
Basically, you will just have to call that URL by a Launcher and the Store will start checking for app’s updates immediately!
Update: I have also checked that URL in Windows 8.1 and can confirm that it still works in the new Store.