Windows 8.1 development with C# and XAML carries a lot of similarities with developing Windows Presentation Foundation (WPF) applications. Well, they both use XAML and C#. And many of your existing skills with user interfaces (UIs) and program code can be leveraged for Windows 8.1 apps. But there are a lot of differences, as well. Windows 8.1 apps are touch-centric (but also support mouse and keyboard interactions). There are specific design guidelines, quite contrary to WPF development. The isolation level for Windows 8.1 apps is much higher than WPF, presenting a new level of safety and security, as well as unique challenges when working with data. Apps are deployed through a central store (as opposed to click-once deployment or Microsoft Installer packages).