@Jovanwe 

Hi!

Sorry for the delay.

Please refer to the following link to change the device name：

1. on the overview page of the APP, choose the target client;
2. on the next page, there would be a pen symbol where you could click and change the name;

as for the indirectly way,  I guess you could change the device name on itself, such as the device name of your smartphone;

Thank you very much!

@TP-Link_Deco Sorry, but your answer is not the solution for me. 

I want to change the name "Generiek" to the name (chosen by me) of the device corresponding with the IP-adress.

But this page doesn't accept changes. Although that's the meaning of this page, I believe. 
kind regards,

jovanwe