Can I Develop Windows 8.1 App using VS 2012?

 The Short Answer is NO. I had a customer looking to use VS 2012 to develop Windows phone 8.0 and 8.1 Apps.

 The current Windows Phone 8.0 SDK is compatible with Visual Studio 2012 (Update 2) and higher (see https://dev.windowsphone.com/en-us/downloadsdk) .

 

To develop Windows Store Apps for Windows 8.0 you generally need Visual Studio 2012 or higher. Different editions of Visual Studio may introduce additional restrictions.

To develop Windows Store Apps for Windows 8.1 you generally need Visual Studio 2013 or higher.