Dells XPS 13 is a very popular and successful Ultrabook. In 2017, Dell wants to build on that success-story with a new model, the XPS 13 Convertible. This new model is supposed to take Lenovo´s Yoga and the HP Spectre x360 head-on.
http://www.notebookcheck.net/Dell-XPS-13-Convertible-leaks-shortly-before-CES-2017.189750.0.html