Migrating from Windows 8 to Windows 8.1
Windows 8.1 is the second release of Windows 8. There are already tens of thousands of apps written for Windows 8.
If you already created a Windows Store app for Windows 8 and you want to migrate the app to Windows 8.1 then the process is dead easy. When you open your Windows 8 app in Visual Studio 2013, Visual Studio recommends retargeting your app to Windows 8.1 (see Figure 1.35).
FIGURE 1.35 Retargeting to Windows 8.1
You can right-click your project in the Solution Explorer window and select the menu option Retarget to Windows 8.1 to migrate your app to Windows 8.1.
Retargeting your app updates all of your script references to point to the Windows Library for JavaScript 2.0 instead of the Windows Library for JavaScript 1.0. If you prefer, you could do this by hand by adding a reference to the Windows Library for JavaScript 2.0 to your project and updating the <script> tags in all of your HTML pages.
After you retarget your app, you might need to make code changes. For example, as I mentioned earlier in this chapter, Windows 8.1, unlike Windows 8, no longer supports a snapped view state. A list of all of the deprecated Windows 8 application programming interface (APIs) is displayed after you retarget your app.
This might be obvious, but I am going to say it anyway. Apps written for Windows 8.1 won’t run on Windows 8. The Windows Runtime in Windows 8.1 has changed so you won’t see Windows 8.1 apps in the Windows Store on a computer running Windows 8. You still can use Windows 8 apps, on the other hand, with Windows 8.1—you can install both Windows 8 and Windows 8.1 apps from the Windows Store on a computer running Windows 8.1.