Nuki Smart Lock
Apple new iOS 15 includes a new Home Keys feature where a digital key for HomeKit-enabled door locks can be stored in Apple Wallet (on iPhone and Apple Watch) and easily shared:
HomeKit-enabled door locks that support iOS 15’s new Home Keys feature can store a digital key in the Wallet app.
Allows easier sharing of digital keys eg. with guests, cleaners etc without them needing to download the Nuki app.
Avoids reliance on the Nuki app, eg. if the app is broken you can still open the door with the Apple Wallet.