@macuser_22 Yes. As I wrote in my disappeared and now reappeared post "I think both of us know there isn't much value to continuing this discussion." Intuit made a decision. I understand that it is a business decision that Intuit made. As you point out (not in exactly these words), there are tradeoffs in all business decisions. I happen to think that it is an unwise decision, especially this year because of Apple's migration from Intel CPUs to Apple silicon.
However, I don't expect anyone reading this forum to accomplish any more than just showing Intuit how they are losing customers and perhaps induce Intuit management to reconsider (for future years) the tradeoffs inherent in their decision.
The main reason that I am continuing to post to this thread is not with expectation of changing anything, but just to correct inaccurate information. People have written that currently supported Apple development tools (Xcode and SDKs) can't compile code for deployment targets earlier than the versions of macOS that Apple currently supports. That is not true. Currently supported Apple development tools can compile code for deployment on the following versions of macOS: Mavericks, Yosemite, El Capitan, Sierra, High Sierra, Mojave, Catalina, and Big Sur. Everyone should understand that it is Intuit's, not Apple's, decision to develop TurboTax 2020 so that it only runs on Mojave, Catalina, and Big Sur. The reason that other software vendors have no problem releasing their new software so that it runs on older versions of macOS is that those vendors made the business decision to support all the deployment targets that the currently supported Apple development tools can support as deployment targets.
You wrote "Apple officially drops support for 10.13 in Jan 2021, since TurboTax 2020 is for the 2021 filing season, 10.13 will not be supported during the life of TurboTax 2020." As a minor nitpick, I thought that Intuit supports download customers re-downloading TurboTax for up to three years, so that they can produce and file amended returns. Apple supports the current and two previous versions of macOS (and since Apple releases a new version each year, that turns out to mean supporting a macOS version for three years). So it would appear that for filing amended returns, if you used the oldest supported version of macOS when preparing your return and three years later your prepared an amended return with the same version of TurboTax running on the same version of macOS, Intuit would be supporting running TurboTax on a macOS version three years older than the oldest version of macOS supported by Apple. (But of course, that version of macOS was supported by Apple at the time that version of TurboTax was released.)
