if your maintenance is running you should have received already your SUP 2015 license data by your supplier approx. in November 2014. Be aware, that license data of older SUP versions as e.g. your SUP 2014 won't work with the recent SUP 2015.
if you do have the SUP 2015 license data and don't wanna user the SUP 2014 version further, remove the license data in SUP 2014 via "Help > License" and enter your SUP 2015 license data either in the splash dialog resp. "Help > License" at the new system. An active internet connection and a LAN adapter as well as a working MS Internet Explorer v9+ resp. Apple Safari is required for doing this.
hth