https://tools.ietf.org/html/draft-ietf-core-senml-10#section-12.1 has:
| K | kelvin | float | RFC-AAAA |
| Cel | degrees Celsius | float | RFC-AAAA |
The issue is that neither of the above have an asterisk by them, so both are recommended and per Carsten’s definition of “units” during the meeting (i.e., where the reference point is separate from the units), then Kelvin and Celsius have the same units as they only vary by what the reference point is.
Dave's comments: