How it works
Since Windows Phone 8.1 apps are now built on the same WinRT platform as Windows apps (also known as Windows Store apps), it's now essentially just a single platform that supports all Windows devices. We have decided to follow the same pattern as Microsoft and expand our entire WinRT collection of controls into the Windows Phone 8.1 space.
So yes, this means our Windows Phone 8.1 controls are packed with controls and features from Studio for WinRT all in one licensed bundle. You don't have to wait for us to slowly build a new "Universal Studio" one control at a time and rewrite your apps.
We're calling this WinRT update "beta" for the Windows Phone controls because it had a shorter testing cycle in order to get it public sooner, and we have a few missing controls in the first update. You can see the full list of which controls are supported in both Windows and Windows Phone.
How to get started
First, you need to download and install the 2014 v2.5 update of Studio for WinRT. Or you can use any update since then if you're reading this in the future. This includes an updated v2.5 version of our Windows 8.1 controls and the new extensions for Windows Phone 8.1 as a separate VSIX installation. To install the Windows Phone extensions follow the readme that's in the zip.
For instruction on how to use the controls in Visual Studio, check out this short video:
How much code and XAML can you share?
For a brief history lesson, ComponentOne Studio for Windows Phone and Studio for WinRT XAML controls were always near 100% identical to begin with. You could share code and output Windows Phone 8.0 apps along with Windows Store 8.1 apps by linking files and performing any other tricks possible in Visual Studio.
Now with Windows Phone 8.1, most of the changes to the controls are internal changes as we moved from the Windows Phone Silverlight platform to the WinRT platform. Users of our controls will not notice too much difference. But now, not only can you share code files by linking them between projects, you can take full advantage of the Universal Windows App template and share as much code and XAML between projects as you need.
If you still need to target older devices like Windows Phone 8.0 or 7.1, you can continue to use the Studio for Windows Phone Silverlight controls and multi-target using existing techniques. These controls still work in Windows Phone Silverlight 8.1 as well if you upgrade your apps.
We're excited about the new "all-in-one" Studio for WinRT XAML and we hope you are too! Please download the update and let us know your feedback either here, or in our forums.