Photo via Apple (CC-BY)
Sierra brings a whole bunch of neat productivity features to the Mac, including tabs in apps, a Universal Clipboard that carries your copy/pastes between iPhone and your desktop, and a ton of new Siri tricks.
For Apple Watch users, the update adds an automatic unlock feature that syncs your Mac with your smartwatch and unlocks your computer when you open it without requiring you to type in your password.
You can read more about Sierra's new functionality in our full rundown.
The macOS Sierra download weighs in at 4.77GB, so make sure you have a good chunk of free space before venturing to the store to download it. As with the past few Apple desktop OS downloads, Sierra is available for absolutely no charge.