Apple announced macOS Sierra back in June at its developer conference, and after a beta testing period that went on for the past few months, the new software is finally ready for the general public.
The company has made the release available today, as a free upgrade to Mac users. macOS Sierra (version 10.12 if you're keeping track) can be grabbed through the Mac App Store, and it's going to be a 4.77GB download - so make sure you get it on a decent internet connection.
While this isn't a big update by any stretch of the imagination, it still comes with many new features. For example, Siri is built-in, Auto Unlock lets you log in faster, Apple Pay is available in Safari, and tabs are now a part of every app.