Jan 28, 2020 And as updates that change the macOS version number become available, this article is updated to show the latest version of that macOS. If your Mac is using an earlier version of any Mac operating system, you should install the latest Apple software updates, which can include important security updates and updates for the apps installed.
Is your Mac up to date with the latest version of the Mac operating system (macOS or OS X)? Is it using the version required by some product or feature? Which versions are earlier (older) or later (newer, more recent) than the version currently installed? To find out, learn which version is installed now.
If your macOS isn't up to date, you may be able to update to a later version.

From the Apple menu in the corner of your screen, choose About This Mac. You'll see the macOS name, such as macOS Mojave, followed by its version number. If some product or feature requires you to know the build number as well, click the version number to see it.
This example shows macOS Catalina version 10.15 build 19A583.
Jul 09, 2018 Final version of macOS High Sierra is available! The list is: The macOS High Sierra 10.13.6 Update adds AirPlay 2 multiroom audio support for iTunes and improves the stability and security of your Mac. This update is recommended for all users. AirPlay 2 for iTunes: Control your home audio system. Feb 16, 2019 It's been awhile since I checked the available full installers for High Sierra. Haven't seen this 17G66 build version before. Has anyone used the 17G66 installer for High Sierra 10.13.6 on MP5,1's? Cannot find documented info on this forum or any Wiki posts. 17G2208 believe was just for.
These are all Mac operating systems, starting with the most recent. When a major new macOS is released, it gets a new name, such as macOS Catalina. And as updates that change the macOS version number become available, this article is updated to show the latest version of that macOS.
May 28, 2018 PhoneRescue 3.7.0.20180523 – iOS data recovery program. May 28, 2018 PhoneRescue is an ultimate iOS data recovery program designed for retrieving your lost photos, messages, contacts, notes and more on your iPhone, iPad and iPod touch. 
If your Mac is using an earlier version of any Mac operating system, you should install the latest Apple software updates, which can include important security updates and updates for the apps installed by macOS, such as Safari, Books, Messages, Mail, Music, Calendar, and Photos.
| macOS | Latest version |
|---|---|
| macOS Catalina | 10.15.3 |
| macOS Mojave | 10.14.6 |
| macOS High Sierra | 10.13.6 |
| macOS Sierra | 10.12.6 |
| OS X El Capitan | 10.11.6 |
| OS X Yosemite | 10.10.5 |
| OS X Mavericks | 10.9.5 |
| OS X Mountain Lion | 10.8.5 |
| OS X Lion | 10.7.5 |
| Mac OS X Snow Leopard | 10.6.8 |
| Mac OS X Leopard | 10.5.8 |
| Mac OS X Tiger | 10.4.11 |
| Mac OS X Panther | 10.3.9 |
| Mac OS X Jaguar | 10.2.8 |
| Mac OS X Puma | 10.1.5 |
| Mac OS X Cheetah | 10.0.4 |