HomeKit is giving users more choice about what controls the smart home network in iOS 18, by selecting what device acts as the active Home Hub.
HomeKit's Home app on iOS
HomeKit prefers to have a Home Hub, a device designated as the main point of contact on the network for all other hardware. A home could have multiple devices that can act as the Home Hub, but you couldn't previously designate one as the primary device for the task.
In practice, this meant that the assignment rotated, sometimes to a device on the periphery of your network.
Though Apple mentioned multiple changes to HomeKit during its keynote, the HomeKit subreddit on Reddit spotted an unannounced change in the Home app.
The new Preferred Home Hub option in the Home app [Reddit]
Users can now select a "Preferred Home Hub" in the Home app. A user can specify which potential Home Hub is the primary one from the list of potential devices.
If the preferred option is disconnected or unavailable, HomeKit will switch to one of the others until the selected device becomes available again.
For users, the option to select a Preferred Home Hub can be useful. For example, they can set newer devices as the designated Home Hub instead of older hardware.
If there is a slow connection to a Home Hub device, the option also ensures that device will only be used as a backup.
The change is appearing in the iOS 18 Home app, but it does require that beta software is installed on the HomePod and Apple TV units for it to work.