The reference implementation, while historically important, has largely been displaced by more secure/performant implementations (ntpsec, chrony), or by in-house implementations (Amazon, Google).
Notably NTPd doesn't support leap-smear, which means those who absolutely must have monotonic time can't use it at all.
Notably NTPd doesn't support leap-smear, which means those who absolutely must have monotonic time can't use it at all.