This fall, Apple will release macOS Sierra, a major update to the Mac operating system. This FAQ will answer some of the general questions you may have to help you learn what it’s all about and whether you should install it on your Mac. We’ll update this FAQ with more questions, answers, and details as the release date approaches.

macOS? What happened to OS X?

Apple decided to change the name in order to fit with the names of iOS, watchOS, and tvOS. So no more Roman numerals (or that annoying person who insists on calling it “OS ex”).

Some trivia, if you’re interested: macOS isn’t entirely a new name. Before version 10, Apple used to call its Mac operating system Mac OS, with the last version being Mac OS 9. Apple change the name to OS X when version 10 was released in 2001.

Does Apple still name its Mac operating systems after California locations?

Yup. This one is macOS Sierra.

More trivia: Sierra refers to a mountain range in central and eastern California. It’s also called the Sierra Nevada, and a small part of the range lies in the state of Nevada. (Sierra is Spanish for mountain range and Nevada is Spanish for snowfall.) Lake Tahoe, a popular snow sports location in the winter and a frequently-visited lake in the summer, is located in the Sierra. Yosemite National Park (which is home to El Capitan) is also there. Mount Whitney, the highest peak in the contiguous United States, is in the Sierra.

What version of the Mac operating system is this?

10.12.

Apple iCloud Drive will now let you access documents on saved to the Desktop on any Mac.

When will it be available?

macOS Sierra is available now. It started shipping on September 20, 2016.

How much will it cost?

Apple makes its operating systems available for free, and macOS Sierra will be no different.

How do I get macOS Sierra?

Though the App Store.

Will it run on my computer?

Here’s the list of Macs that will run macOS Sierra.

MacBook (Late 2009 and later)

MacBook Air (2010 and later)

MacBook Pro (2010 and later)

Mac mini (2010 and later)

iMac (Late 2009 and later)

Mac Pro (2010 and later)

Compatibility with Sierra, however, isn’t as simple as checking to see if your Mac is on the list. Here’s the complete story on Sierra compatibility, and Apple has information on what features are available based on region and language.

Should you upgrade to macOS Sierra?

Once you’ve determined that you have compatible hardware, deciding to upgrade is a personal choice. If you absolutely depend on a specific app and would be crippled without it, you should wait to make sure from that app developer that their software will work with macOS Sierra.

If you do decide to upgrade, make sure you back up your data first. If you end up having a serious problem, you can revert back using your backup.

I heard that Siri is in macOS Sierra. True?

It’s true. There will be a Siri icon in the dock. Clicking on it activates Siri. You can use it as you would with your iPhone, like say, if you need directions, are trying to find a nearby restaurant, or want information on a topic.

You can also use it to find files on your Mac. For example, you can tell Siri to find all the files with the word “report” in it, and Siri will list those files.

Siri also lets you work with other Apple apps. You can take Siri results for, say, an image, and then drag and drop the image into a Keynote presentation. You can have Siri find a location in Maps, and then drag the location into an email.

Apple has not announced a third-party API for macOS Siri. Siri works only with Apple apps. So, for example, if you want Siri to read your emails to you, you must use the Apple Mail app.

I also heard that Apple Pay is coming to the Mac. Yes?

Yes. When you’re shopping online and you see an Apple Pay button, you can click on it to use Apple Pay to pay for it. You still need your iPhone, however. Apple Pay on the Mac uses the iPhone’s Touch ID to verify your purchase; you can also press your Apple Watch side button twice.

Apple Apple Pay on the Mac is coming with macOS Sierra.

Speaking of the Apple Watch, why can’t I use it to unlock my Mac?

Well, with macOS Sierra, you can. When your Mac has been inactive or you’re powering it up and you get to the login screen, a feature called Auto Unlock will sense your Apple Watch and instantly log you in. No more typing your password.

What are the other new features?

Here’s a list of the major new features showcased at Apple’s Worldwide Developers Conference. They include iCloud Drive Desktop access, Optimized Storage, Picture in Picture, Tabs, and Universal Clipboard.

Some of the other neat features:

Apple File System, a new file system not only for macOS but also for iOS, tvOS, and watchOS. Launches in 2017.

enhanced Messages.

support for third-party app integration with the Contacts app.

Apple Music improvements.

Photos for Mac gets new features, too. A new Memories tab automatically creates slideshows based on events, places, or people. There’s also support for extensions for Photos that will allow for editing of Live Photos. When you make an edit, it will apply to the whole Live Photo, not just the one sequence you edited.

Safari will have a major change in the way it handles content that uses plug-ins like Flash, Silverlight, and QuickTime. You’ll see an alert that tells you the plug-in is not installed, and you’ll need to click on a “Click to use” button to see the content. Apple is doing this to force websites to load—if it’s available—HTML5-compliant media implementations.