Is your Mac up to date with the latest version of the Mac operating system? Is it using the version required by some product that you want to use with your Mac? Which versions are earlier (older) or later (newer, more recent)? 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.
I did a factory reset of my 2012 MacBook Pro to Mountain Lion (Original OS that came with 2012 MacBook Pro) and updated it to macOS Catalina. Before Updating to macOS Catalina, I updated the system to High Sierra. Well the Mac OS X Mountain Lion 10.8 is the dawn update for MacBook users especially. Apple focused on decoding and solving the bugs that erupted among the various MacBook users with the Beta version release of the Mac OS X Mountain lion. The Mountain Lion OS also improved the user interface of the MacBook interface. Use About This Mac to see the version of Mac operating system installed on your Mac, and find out whether it's the latest version.
Which macOS version is installed?
Update From Mountain Lion To Catalina

Update Mountain Lion To Catalina Ferry
From the Apple menu in the corner of your screen, choose About This Mac. You should see the macOS name, such as macOS Big Sur, followed by its version number. If you need to know the build number as well, click the version number to see it.
Update Mountain Lion To Catalina Islands
Which macOS version is the latest?
Update Mountain Lion To Catalina Canyon
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 Big Sur. 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 that are installed by macOS, such as Safari, Books, Messages, Mail, Music, Calendar, and Photos.

macOS | Latest version |
---|---|
macOS Big Sur | 11.2.3 |
macOS Catalina | 10.15.7 |
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 |
