GeneXus X Evolution 3 includes a Windows Phone Generator. Below are the requirements to generate these applications:
1. PC with Windows 8.1 Professional, Ultimate or Enterprise.
2. Microsoft Framework 3.5 or upper installed. It's installed as a Windows feature (using "Turn Windows features on or off").
3. SQL Server (Express Edition supported) installed or accessible via the network.
4. Visual Studio 2013 (Community edition or better) is needed.
5. Windows Phone 8.1 SDK.
The Windows Phone 8.1 SDK is installed with Visual Studio 2013 for Windows with Update 2 or later. More information here.
You can download the Visual Studio 2013 latest update from here.
The SDK will install an emulator where you can run your apps. If you have a Windows Phone device where you want to test your apps you need to register your device for development. More info about that here
Notes:
1. Windows Phone 8 Emulator runs as a virtual machine on Hyper-V. To run the emulator, your computer must meet the requirements to run Hyper-V.
See this link for information about enabling Hyper-V in Windows.
See this link to enable BIOS settings required by Hyper-V here.
2. If you want to try your apps on a physical device you need to unlock it following these steps: How to register your phone for development for Windows Phone