I am looking to purchase an older used Apple Watch. I am only really interested in the zones feature. Would anyone know how old I can go and still have access to this feature? When I reached out to Apple support they said only series 8 and the ultra have it which maybe that’s correct but seems crazy.
Can confirm it works on my series 7. Also, it works for any workout type, just needs to be enabled. See my other comments in this thread to see how to enable it for any workout type, including strength training.