Apple’s new HomeKit architecture is a ground-up, under-the-hood rebuild of the company’s Apple Home smart home platform. Apple says it “will improve the performance and reliability of the accessories in your home.” First announced at WWDC, this new foundation for Apple’s smart home is part of the company’s support of the smart home standard Matter.

Following a false start late last year, when the option to upgrade to the new architecture was released with iOS 16.2 but was quickly pulled following multiple user complaints, Apple is trying again. With iOS 16.4, which released this month, users can once again choose to enable the new Home architecture.

However, upgrading is entirely optional. And if you use an iPad as your main Apple Home hub, you will not want to upgrade. iPads are no longer supported as Home hubs in the new architecture — but they can continue to work as one if you don’t upgrade.

Also, if family members have older iPhones and iPads that can’t upgrade to 16.4 or Apple Watches that can’t do watchOS 9.4, they will lose access to controlling the home if you update to the new architecture.

If you’re ready to go for it, though, and want to try out Apple’s promised faster, more stable Home setup, then read on.

What to do before upgrading

There are several steps you need to take to get ready for the upgrade, and you won’t be able to update until you complete them. Remember, only the registered owner of the Home app can do the upgrade.

• Make sure you have an Apple Home hub — either an Apple TV or a HomePod.
• Update any Apple device that accesses the Home to the latest OS. That’s 16.4 on iPhone, iPad, HomePod, and AppleTV; watchOS 9.4 on the Apple Watch; and macOS Ventura 13.3 on your Mac (more instructions on updating just below).
• If you try to upgrade without doing this first, you’ll get a notification telling you which devices need to upgrade. If you proceed without updating them, those devices will lose access to Home until they are updated.
• You can update your HomePods in the Home app.
• Your Apple TV needs to be updated on the device — go to Settings > System > Software Updates, and select Update Software.
• For your Apple Watch, open the Watch app on your iPhone, select the My Watch tab, and choose General > Software Update.
• Make sure the devices of people you’ve invited to your Home are updated, too. If you don’t, they will lose access.

How to upgrade

You should be greeted with a pop-up that says Upgrade Home the first time you open the Home app once you have upgraded your devices. Tap upgrade and follow the steps. If you don’t see this screen or if you hit the Upgrade Later option, then follow these steps to initiate the upgrade.

1. Open the Home app on your iPhone or iPad running the latest version of iOS or iPadOS. (You can also use a Mac running the latest version of macOS.)
2. Tap the More button in the top right-hand corner.
3. Tap Home Settings. (If you have multiple Homes, choose one, then select Home Settings. All of your Homes will be updated.) 
4. Tap Software Update.
5. Tap on the notice saying Home Upgrade Available Learn More, and follow the steps.

Once the upgrade is complete — which should only take about 30 seconds — you should start to notice improved response times and overall better stability of your smart home. The Upgrade Home option will disappear from Home Settings.

If you run into any problems — such as a household member no longer having access or automations no longer working — try rebooting all of your Home hubs and see if that fixes the issue. Rebooting your iPhone can also help: sign out of iCloud on your device, reboot, and sign back in again.

Update April 20th, 1PM ET: Originally published on December 16th, 2022. Added that the option to upgrade to the new Home architecture was removed for a short while and is now available again.