Build apps that target the highly anticipated update of Windows 8 coming later this year. Studio for WinRT XAML now supports Windows 8.1 Preview with Visual Studio 2013 Preview. Get this latest update only if you plan to build Windows Store apps targeting 8.1. Download Studio for WinRT XAML 8.1 Continue to use the 2013 v2 release for apps based on Windows Runtime 8.0. You can install the 8.0 and 8.1 versions of Studio for WinRT XAML side by side if you so choose. There is a known design-time issue in Visual Studio 2013 preview that may show the controls as empty boxes on the design surface. This should not affect the app behavior in any way. Also, this release marks the first time the Studio for WinRT controls are separated into multiple SDKs, or libraries. So if you only need to use the C1PdfViewer control, your project will reference the base C1.Xaml library and the C1.Xaml.PdfViewer library only rather than the entire Studio for WinRT SDK. This reduces the bloat of your app. The entire Studio for WinRT XAML splits out into about 20 separate libraries. To determine which libraries you need, drop the controls from your toolbox and the references will be automatically added.