Why does my Mac show macOS X instead of macOS 15.3.2 on external connections?

margy129 wrote:

Why does my Mac show macOS X instead of macOS 15.3.2 on external connections?

Because the service that you are connected to (Grammarly in this case) is still using the original name for macOS. It senses that you have macOS on your Mac but its return message hasn't been updated. It's nothing to worry about and you cannot change it. Grammarly needs to change the text on their end. Ditto any other online service you connect to that may list OS X instead of macOS.

The Mac operating system was originally called System x (1,2,3,4). Then changed to Mac OS (5,6,7,8,9) around 1987, the changed again in 2001 when Apple released what we know as Mac OS X. (BTW, Mac OS X was a completely new operating system.) The name was later shortened to just OS X. In 2016 Apple changed the name again, this time to macOS. In general use, the names are interchangeable.

In the HTTP/S protocol, there is a spot to report browser version and OS version. Providing the OS version is a security issue because it allows attackers to focus on specific exploits. Apple stopped reporting the actual macOS version at that version of Catalina.

Ran out of editing time. The last sentence should read:

In general use, the OS X and macOS names are interchangeable.