Probably a bunch of devices will just jump to 1970 tbh. Through if you do it properly you add some fixed known min . time (like manufacturing time, or time of

Probably a bunch of devices will just jump to 1970 tbh. Through if you do it properly you add some fixed known min . time (like manufacturing time, or time of the last system software/is update) and if the NTP time is noticable below the min time you increase the epoch by 1. E.g. in you case the device could know it's revision had a min. time of idk. 2015. Then if it receives 1973 it knows it's 3 years in the next epoch. But as anyone can guess there will be devices which didn't implement that at all and will end up in 1970. Or which require setting time by hand and will end up in 1970 because it truncates to 32bits at some point or similar. Through some embedded devices might happen to avoid it. Like due to special reasons they might use a non-unix epoch.