But, unless you're really impatient, it's always safest to wait to upgrade until Apple releases the first point release, which typically arrives three or four weeks after the initial launch. If you already have a Mac dating back to 2010 (or a MacBook or iMac from late 2009), an upgrade to Sierra gives you dozens of advantages-including faster performance-and, as far as I can tell, no major disadvantages. The biggest change is the addition of Siri, Apple's voice-activated assistant, now accessible from Mac laptops and desktops after a long residence on the iPhone and iPad.
If you've been using OS X for years, everything except the name in macOS Sierra will look familiar, though with notable improvements throughout.
Now the newly renamed macOS joins iOS, tvOS, and watchOS in the tightly interconnected Apple ecosystem. With the advent of Sierra as a free download from the App Store, OS X is no more. When you upgrade your Apple computer to macOS Sierra, the hardest thing you'll have to learn is its name.
