iOS 15 didn't focus heavily on improvements to HomeKit and the Home app, but there are some notable features like expanded HomeKit Secure Video support and new Siri functionality.
This guide highlights all of the features that are new to HomeKit in the iOS 15 and iPadOS 15 updates.
iOS 15 introduces a new iCloud+ service that offers privacy-based features like iCloud Private Relay and Hide My Email, but the feature also comes with HomeKit Secure Video improvements.
With iCloud+, Apple is increasing the number of HomeKit Secure Video cameras supported with each iCloud plan. There have been no changes to iCloud plans and all iCloud plans are now iCloud+ plans, but more camera footage can be stored.
The $0.99 per month 50GB iCloud+ storage plan offers support for one HomeKit Secure Video Camera, which is a major improvement because previously, the 200GB plan was required to use HomeKit Secure Video.