Happy to provide clarifications on the compatibility of these versions in QuickBooks. Thus, the confusion will be eliminated, SandyAfrica.

As long as you meet the minimum operating system requirements for QuickBooks Mac, you'll be able to run and apply updates, including the R13 release. 

But before that, I'd suggest backing up your company file for future use. 

Each version of the Mac platform has different operating system requirements:

• QuickBooks Mac 2019: At least Mac OS X v10.12 (Sierra); Supported by Mac OS X v10.14 (Mojave), 10.13 (High Sierra).
• QuickBooks Mac 2020: At least macOS 10.14 (Mojave); supported by macOS 10.14 (Mojave).
• QuickBooks Mac Plus 2022: An operating system of at least Mac OS X v11.3 (Big Sur) or later.

If you need the full details of the system requirements for QuickBooks Mac, check out this article: System requirements for QuickBooks Mac Plus 2022.

Feel free to leave a comment below if you have additional questions about the latest software update. I’ll be glad to answer them for you. Have a great rest of your day.