Apple tv+ with older mac

My earlier link also says: On the web: Go to tv.apple.com and sign with your Apple ID or create a new one to watch an Apple TV+ subscription.

You can watch it in the browser, at https://tv.apple.com/ on a Mac with macOS Mojave or earlier.

Devices you can use with the Apple TV app and Apple TV+ - https://support.apple.com/HT210740

Mac: Update to the latest version of macOS.