> The problem with TAI is that you cannot convert a future time to UTC if it is farther than 6 months or so in the future [...]
Centimeter's argument is that such time should not be converted to TAI in advance, much like the local time for the future point (since the local time zone offset may change). All points on this also apply to the local time, e.g. it's already true that non-updatable embedded systems can't reliably do the local time calculation.
They can’t do local time, but they can do UTC (and do it) without much investment if you run an NTP client. (Have 500 or so such units deployed, SNTP was giving too much trouble, switched to chrony at some point and those units require much less support)
Centimeter's argument is that such time should not be converted to TAI in advance, much like the local time for the future point (since the local time zone offset may change). All points on this also apply to the local time, e.g. it's already true that non-updatable embedded systems can't reliably do the local time calculation.