2036 date limit

The 2036 date limit is a forthcoming limitation of early versions of the Network Time Protocol (NTP) used by classic Mac OS and older versions of Mac OS X and Unix.

The 64-bit timestamp used by NTPv3 and earlier will cycle from February 7, 2036 at 06:28:16 back to January 1, 1900. The NTPv4 specification was proposed in 2010 to address the issue by adopting a 128-bit value. Due to security concerns, Apple no longer relies on NTP as of macOS Mojave (10.14) in 2018 and instead implemented its own timed function.