You don't need the same Year QB as the data file is from.

"And then even if you can figure out what version of quickbooks was used to create the backup, you will have to buy the older version and it probably is not available, even from Intuit."

You need the same year or newer, because the program will Restore, and also Update if need be.

And any Pro or Premier File can be restored using either Pro or Premier. Enterprise restores any file, but it also Upgrades it to Enterprise, so there is no going back to Pro/Premier.

And if the file is really old, you might need to update in interim jumps, because Intuit has a 3-year lifecycle for the program. Intuit would update an older file to QB 2019 for you, for instance.

This is a False Notice: "In my view the Quickbooks software product should bear a large warning on the label disclosing each version of Quickbooks is completely incompatible with all of the others."

That's never been true.