I have just been at Kenneth's home and got my twizy upgrade, it's a 2018 model. Have to say that, on the one hand, that was exciting and, on the other hand, I'm really pleased.
Some things stop working after the update though. But none of it matters to me. But still good to know in advance.
The trip meter does not count anymore,
ecometer (the three stretches at the top) does not work anymore,
you do not have to turn the nodes until it gives sound without turning to position two and driving,
speed limitation one back (15km / h) is gone, and 85km / h barrier is gone,
that's all I've discovered so far.
I've noticed that my car pulls less power after updating even though I'm driving more aggressively now! In addition to the new power, it's great to see the cells load and to what level, to change the regen so it helps to brake and another level of engine brake is amazing!
Kenneth did the job for me to change parts, but with the right tools you can do it yourself! I can say that the update, even though it costs twice the year before 2016, is still worth doing. Joy, control of the car and I think the parts (control unit and powerbox) will keep the value. So thumbs up and do not hesitate. My car is just 2 months old and I'm glad I did it already!