You can use the following configuration for the K33UP:

Manufacturer: Generic/Analogue
3: Black
4: Orange
5: Blue
6: Red
7: -
8: -
9: Violet
10: Green
Terminal: Yellow and the cables from 10

Yes, it works. However, only the command for simple door opening. Functions with a link to the doorbell and so on do not work. Purple Nuki cable to terminal 9, dark blue Nuki cable to terminal 5.

Thanks for the answers. I have decided on a solution via Switchbot Bot....

Information from Koch, which is probably half right according to your statements:

"The Nuki is bus based (you need a TC-BUS system (BVS20), the K3 system is an analogue system, unfortunately that doesn't work."

I also have an old Koch system. The bell has to be connected to power and the door opener to ground. Nuki is not prepared for two different polarity directions. But without bell integration Nuki works great! For more details: andreas.kienast@espas.ch