@Mich_S
stated, in response to whether Mac Desktop 2019 is compatible with macOS 12 Monterey, "As of now the operating system that's compatible with QBDT MAC installation is at least Mac OS X v10.12 (Sierra); Supported by Mac OS X v10.14 (Mojave), 10.13 (High Sierra)."
I don't believe this statement is correct. Intuit officially stated that 2019 R9 and later will run under Big Sur (and, by implication, Catalina). See: Intuit’s support policy for QuickBooks for Mac running on macOS 11 Big Sur (Updated July 16, 2021) at https://quickbooks.intuit.com/learn-support/en-us/product-system-requirements/intuit-s-support-policy-for-quickbooks-for-mac-running-on-macos/00/186292
Which doesn't answer whether 2019 will run under Monterey; only that the information provided by Mich_S is incorrect. My guess is that 2019 will not run under Monterey, at least not officially, and not if it will require updates. Until now, it has been Intuit's policy to supply bug fixes, security patches, and compatibility updates for three years (including the year of release). So I am guessing that 2019 (which actually shipped in fall 2018) has reached end-of-life. Hopefully, someone from Intuit will provide a clear, definitive answer.
What I don't know is whether Intuit will continue to support and provide updates for Mac Desktop 2020 and 2021, now that they've shipped the subscription-based Mac Plus 2022, the new name for Mac Desktop.
As katherinejoyceO of the QuickBooks Team wrote on 25 October, "the Mac OS version Monterey is only compatible with QBDT for Mac 2021." Does that mean Intuit is abandoning Mac Desktop 2020 a year early?
https://quickbooks.intuit.com/learn-support/en-us/other-questions/quickbooks-mac-2021-desktop/00/961...
