Review the Apple software update process
The process to perform a software update involves multiple steps — from the detection of an available update, to downloading and preparing the update, to the actual installation.
Software update detection
After an update becomes available for iPhone, iPad or Mac, it’s detected in one of the following methods:
After the user opens the Software Update settings
Every 24 hours
After a device restarts
If the device is using the default configuration and the requirements for a software updates are met, users can navigate to Settings (on iOS and iPadOS) or System Settings (on macOS) to download, prepare and install the update at a time convenient for them.
Downloading and preparing software updates on iPhone and iPad
When connected wirelessly, iPhone and iPad devices use an over-the-air (OTA) update method that downloads only the components required to complete an update. This update improves network efficiency and enables faster downloads.
iOS and iPadOS software updates are made available in two phases, which determine how they can be downloaded.
iPhone and iPad can download and prepare software updates when connected using Wi-Fi and when connected using mobile data:
When connected wirelessly using Wi-Fi:
Initial availability: Manually by the user from Software Update Settings.
General availability: Manually by the user or using automatic software update downloads.
When connected wirelessly using mobile data:
Initial availability: Manually by the user when their device is connected to a 5G mobile network and has Allow More Data on 5G turned on.
General availability: Manually by the user unless it’s deferred by the service provider on the specific mobile network. In this case, users are informed that a Wi-Fi connection is required to download the update.
When physically connected to a Mac or PC: Through the Finder or Apple Configurator on a Mac or the Apple Devices app on a PC. In this case, a full copy of iOS or iPadOS is downloaded, prepared and installed.
Downloading and preparing software updates on Mac
Similar to updates for iOS and iPadOS, updates for macOS are incremental updates using the OTA update method, which downloads only the components necessary to update the specific device. Incremental updates require a sealed system volume.
Software update notifications
After an update has been downloaded and prepared, a notification is shown to the user and a red icon appears over the Settings app (on iOS and iPadOS) or the System Settings app (on macOS). If automatic downloads are turned off, the notification and badge are shown when the update is detected.
Installing a software update
iPhone and iPad
If a passcode has been configured on the device, users are prompted for it to authorise the update.
Mac
In macOS 12.3 or later, any local user can authorise incremental software updates. Before macOS 12.3, local administrators are required to perform software upgrades. On a Mac with Apple silicon, users must be a volume owner to perform an update.
The Universal Mac Assistant (UMA) is a full installer of macOS and can be used on any supported Mac. The UMA is available using the softwareupdate command-line tool and requires authorisation by a local administrator to be installed.
Automatic installation of software updates (not upgrades) and Rapid Security Responses
After the preparation is complete and users have automatic software updates or Rapid Security Responses turned on, the device uses on-device machine learning to determine a suitable time to install them.
To authorise the update, devices try to use the passcode or password from unlock to perform an automatic update, but may prompt the user instead.
In addition to other software update requirements, Mac computers must have no apps or processes running which block a restart. Mac laptops can have their lid closed.