The updates don’t bring many new features, but are instead focused on security, reliability, and performance. But the release notes on the update screens do list many tweaks if you’re interested in seeing the details.
To install the updates:
macOS: Click the Apple menu > App Store > Updates.
- iOS: Tap Settings > General > Software Update.
- watchOS: First upgrade your iPhone, then on your paired iPhone tap the Watch app > General > Software Update. This update might take about an hour to install and will require you to leave your Watch on the charger.
- tvOS: navigate to Settings > System > Software Update.
If the updates aren’t available give it some time and try again later. Sometimes it takes a while for the updates to roll out across all of the update servers.