The new architecture was first introduced in December last year as part of iOS 16.2, but got pulled not long after launch due to several bugs impacting everything from set-up to sharing permissions to basic features of the connected smart home devices. But the good news is it's back in the newest version of iOS, as well as iPadOS 16.4 and macOS Ventura 13.3, the other recent software updates that Apple's pushed out.
You'll find the upgrade option by going to the Home app's three dots menu, then Home Settings and either Learn More or Software Update under the Home Upgrade Available banner. However, you don't need to do this if you already upgraded your set-up during the original availability window, since the update will happen automatically.
Updating the Home app allows you to automatically convert your existing set-up to the new architecture, which is certainly convenient. In return for updating, Apple claims performance will be more reliable and quicker for all your connected smart home devices.
Further Home updates
This update pairs nicely with the fact that Apple Home and other HomeKit apps now also work with the Matter smart home standard, Supported by Apple as well as Google, Amazon and many other companies, it makes using devices from multiple brands far easier than before.
In Apple's latest iOS 16.5 beta release, we've yet to see evidence of any further HomeKit changes. If Apple does have anything big planned for its smarthome tech, then perhaps we'll see it introduced as part of WWDC 2023, where we expect to see iOS 17 and other upcoming Apple software make their first appearances.