First generation Decora Smart Wi-Fi products (DWxxx) were are not compatible with Homekit technology. For first generation Decora Smart the Homekit compatible products were the DH1KD, 1,000w dimmer, DH6HD 600w dimmer and the DH15S 15A switch.
In early 2021 Leviton introduced the Decora Smart Wi-Fi 2nd Gen Switch and dimmer (D2xxx). These products continue to work with the My Leviton app and include support for HomeKit technology.
For more information please refer to article Do First Generation Decora Smart® Wi-Fi Products work with HomeKit?