Assuming correct implementation of the NTP spec and adherence to the "eras" functions, NTP should be resistant to this failure in 2036.
The problem being so many micro-controllers, non-interfaceable or cheaply designed computers/devices/machines might not follow the standards and therefore be susceptible although your iPhone, Laptop and Fridge should all be fine.
You have 13 years to upgrade to 64-bit ints or switch to a long long for time_t. Lots of embedded stuff or unsupported closed-source stuff is going to need special attention or to be replaced.
I know the OpenFirmware in my old SunServer 600MP had the issue. Unfortunately I don’t have to worry about that.
Most 32-bit games written for some form of Unix will use the system time_t if they care about time. The ones written properly, anyway. Modern Unix systems have a 64-bit time_t, even on 32-bit hardware and OS. If it’s on some other OS and uses the Unix epoch on a signed 32-bit integer that’s another design flaw.
You’ve got 13 years to update unless any of your code includes dates in the future. Just stay away from anything related to mortgages, insurance policies, eight year PhD programs, retirement accounts…
If you’re managing mortgages or retirement accounts on systems that weren’t ready for 2038 by 2008 you were already missing the biggest bucket of the market.
