Why not ask your question on the H&R Block website?
@syncrasy
I found this on the Web and I guess the main issue would be the part I underlined with “might” being the key. So you would be taking a chance.
To install your tax software, your computer needs to be able to meet several H&R Block software system requirements. Without these basic requirements, the H&R Block Tax Software might not be able to function properly on your computer.
https://www.hrblock.com/tax-center/support/software/technical-issues-software/software-system-requirements/ Should anser your question, wasn't hard to find.
Update for any interested Mac High Sierra users…
I rolled the dice and purchased the H&R Block 2022 software (download). It installed fine, launched, performed the usual updates, allowed me to import my prior year tax file and save a new file, and offered to open a Quicken TXF financial file as usual. It appears to be working normally so far. I'm now proceeding with caution on High Sierra.