You can develop, test, run in the simulator, and build and deploy on device apps for Windows Phone 8. For more information how to start developing for Windows Phone 8 with an existing project, see Enable an Existing Project for Windows Phone 8 Development.
Improved version control
You can create, delete, check out, and merge branches when using integrated version control or third-party version control in both In-Browser and Windows clients.
Introduced the AppBuilder command-line interface
You can download the command-line interface from npm Registry. You can install this version of the AppBuilder command-line interface on Windows and OS X systems. For more information about downloading and installing the command-line interface, see Download and Install the AppBuilder CLI.
Introduced the AppBuilder package for Sublime Text
You can download the package from Package Control. You can install this version of the AppBuilder package in Sublime Text 2, on Windows and OS X systems. The package requires that you have the AppBuilder command-line interface installed on your system.
Support for LESS files in the code editor
You can create new and add existing LESS files. You can compile LESS files into CSS files in both the In-Browser and the Windows clients.