Sierra drivers for both EFI rips have been available from EFI for months.
Don't rely on Xerox or any other manufacturer to keep their drivers pages current with EFI, just use EFI.com for anything related to the RIPs them selves. And don't skip the readme/release notes, you need to run the Fiery uninstaller to remove anything you have first before installing the updated drivers or you will have a bad time.
Having several issues printing since my mac OS was updated to Sierra, I am aware that drivers are not available for this OS but whats done is done now. Im assuming there will be workarounds as this cant be uncommon.
Having deleted the PPDs and reinstalled the printers, as per one of the forum posts to remedy the connection issues, I am now able to send files to the hold and print queues of both our V80 and J75, external Fiery rip presses, but the files appear in the queue as PPML files and I cant do anything with them. Any suggestions?