@ACKMMH1 Since this has all been hashed out in this thread, it might be useful for you to read the posts in the thread.
In summary:
- You are correct that Apple currently supports only 10.14 (Mojave), 10.15 (Catalina), and 11.0 (Big Sur).
- However, according to the Apple document at https://developer.apple.com/support/xcode/ the latest version of the Apple developer tools (Xcode and SDKs) can generate code for a deployment target running macOS versions 10.9 through 11.0 (that is, Mavericks, Yosemite, El Capitan, Sierra, High Sierra, Mojave, Catalina, and Big Sur). See the chart "Minimum requirements and supported SDKs" on the web page https://developer.apple.com/support/xcode/ In particular, see the column headed OS and the Legend below the chart for an explanation of the contents of each of the columns.
