Suggestions for Connecting Mac to Esoteric K0-3 that requires older OS?

I had been using a MacBook Air connected by USB to a K0-3 for several years. The Mac had an older OS, cannot remember which, that was compatible with the K0-3. That Mac was stolen a week ago, and, after trying unsuccessfully to connect my newer Mac with 10.12.6, I got hold of the friendly Esoteric rep in NJ, who called his connection at Esoteric, to find out that the K0-3 does not support USB with Mac OS newer than 10.9, so as far as I can figure, I'm left with a player that I cannot use for streaming with Mac, since, in turn, Mac does not support their older operating systems; I can't just buy a Mac and install an older OS, and even if I found one used, Tidal requires 10.9 or newer (Spotify will soon not support older than 10.9 either), so I would need exactly a 10.9 OS (until Tidal stops supporting that; what a world). There must be a way to stream from my Mac to K0-3 with newer OS, but darned if I can figure out how. Is there something I could use to bridge between the Mac and the K0-3? (I'm actually running, or did run, the computer to UpTone UltraCap to UpTone regen to KO-3. Good times until computer was lifted.
Sounds like the easiest fix is to replace the OS you have with the El Capitan version (10.11.1) below and update the driver to the version here.
Version 273.4.1 Compatible with:
Mac OS X Snow Leopard (10.6.4 or later)
OS X Lion (10.7)
OS X Mountain Lion (10.8)
OS X Mavericks (10.9)
OS X Yosemite (10.10)
OS X El Capitan (10.11.1)

If I understand your question.
Newer Mac's have HDMI.  Try a simple HDMI to USB converter.  Also Toslink works.
Apple also sells "Refurbished" older computer on there site.  I think they come with older os's.  Yeah and they come with full warranty.  I've purchased two over the years and never had issue.