About macOS Sierra :

Welcome to Siri on Mac, bringing you a whole host of new features unique to the desktop. Mac now interacts with iCloud and Apple devices in a whole new way—and much more efficiently. Processing photos, listening to music and exchanging messages has become even more interesting.

No matter what task you’re facing, you can always turn to Siri, your smart assistant on Mac.

Enjoy the iOS features you love, plus new ones optimized for Mac.

Send messages, create reminders, surf the web, and more while you work.

Copy and paste or simply drag Siri search results into your documents.

Save your Siri searches in Notification Center so you can return to them later.

Find files, manage settings, and access system information – just ask Siri.

Copy items from one device to another using the Universal Clipboard.

Copy a quote, image, or video in an app on one device and paste it in an app on another.

Perform authorization automatically with the “Auto Unlock” function.

When you’re wearing Apple Watch, you can sign in instantly—no need to enter a password.

Access files from your Mac desktop on your iPhone in your iCloud Desktop and Documents folders.

Automatically save all your files to your desktop and Documents folder in iCloud, and access them from any device.

Optimized storage makes it easy to free up space on your Mac.

Automatically save rarely used files to iCloud so you can access them when you need them.

Additional tools will help you remove unnecessary files and save even more space.

Organize your desktop with app tabs.

Use tabs to manage multiple windows in Maps, Pages, Keynote, Numbers, and more.

Tabs now work in third-party applications without additional adaptation.

Watch your favorite video and never miss an important game by turning on Picture in Picture mode.

Place videos from Safari or iTunes on top of your desktop.

Rediscover the best photos from your Photos library.

Relive your favorite moments with Memories.

Group photos by the people depicted in them. The Photos app uses advanced facial recognition technology to automatically find photos that include a specific person.

Smart Search recognizes objects and spaces and helps you find all the beaches, all the concerts, or all the dogs in your library.

Discover a whole new Apple Music experience in iTunes.

Discover new music with expert selections and advanced machine learning to help you discover great tracks.

Bring your conversation to life in Messages.

View web pages and videos from the Internet right in the Messages window.

Use convenient and quick Tapback responses.

Express your emotions with big smiley faces.

System Requirements :

General Requirements

▪   OS X 10.7.5 or later
▪   2GB of memory
▪   8.8GB of available storage
▪   Some features require an Apple ID; terms apply.
▪   Some features require a compatible Internet service provider; fees may apply.

Mac Hardware Requirements

For details about your Mac model, click the Apple icon at the top left of your screen, choose About This Mac, then choose More Info. These Mac models are compatible with macOS Sierra:

▪    MacBook (Late 2009 or newer)
▪    MacBook Pro (Mid 2010 or newer)
▪    MacBook Air (Late 2010 or newer)
▪    Mac mini (Mid 2010 or newer)
▪    iMac (Late 2009 or newer)
▪    Mac Pro (Mid 2010 or newer)