There are several iOS clients for Domoticz.
ImperiHome (for iOS and Android) supports all Domoticz devices, and more (Nest, ...).
Domoticz is interfaced through a gateway, ImperiHome, that is community supported in the forum. The gateway works on all PI and Synology Docker.
The app is supported in two languages:
Domotix is avaliable in Dutch, English, French, German, and Italian.
Pilot: Home Automation Control
Pilot: Home Automation Control is available in Dutch, English, French, German, and Swedish.
HomeKit apps via HomeBridge
HomeKit apps via HomeBridge can be installed via npm along with the Homebridge-eDomoticz plugin, followed by picking a HomeKit app from the AppStore (e.g. Elgato Eve or Home.app).