Each box generation must follow a specific certification process.
New production of TaHoma® box (including TaHoma switch, TaHoma DIN Rail V2 and Connectivity kit) have been updated to include the HomeKit specifications:
The setup code is available under each box, and inside the packaging.
If you already have TaHoma® at home (or getting one without HomeKit details): it works too.
Just use the TaHoma® app to initiate the link to HomeKit (see the tutorial on HomeKit directly in the TaHoma® app).