The Carista is a good basic bit of kit just to plug in and check for faults and get info about the van.
It gives fault codes (which you need to look up) and, if you pay for a month or a year, can play around with a few settings.
It isn't as good as VCDS or OBD11 but it is more straightforward to use.
However, it may or may not work for 2015 model - you would have to contact them to find out.