feedback50
Earliest version for me was Cakewalk 2 (midi only) that came bundled with a midi interface I purchased (CMS?).
Bingo! Same bundle I bought late in '88 or early '89. MPU-401 MIDI interface with Cakewalk 2.0a for DOS. Still have the floppy and the metallic red on gray user manual here somewhere. Maybe 25 pages.

CMS = Computer Music Systems IIRC.
P.S. I recall that Cakewalk/Greg Hendershott subsequently had a falling out with CMS over licensing/payments, and I had to whine a little to get my copy of 2.0 registered so I could get the upgrade price for 3.0.