Thurrott reports Microsoft is adding support for leap seconds to Windows 10 Redstone 5 and Windows Server 2019. The newest versions of the company's desktop and server operating systems will now deal with leap seconds in an accurate, UTC-compliant, and traceable way. Interestingly, this will make these two operating systems the first in the world to have full support for leap seconds.
The GIF below illustrates how Windows will deal with leap seconds, which are added approximately every 18 months to synchronize clocks with the Earth's slowing rotation. Instead of jumping straight to the next second, Windows 10 will now display the leap second:
Right now, Windows 10 directly jumps from 16:59:59 to 17:00:00 without a leap second, but it will now include 16:59:60 when there is an actual leap second. That one extra second is quite important for time accuracy, especially with increased demand for higher accuracy time from government regulations, according to Microsoft. The company says it will not include an option for leap second smearing where the extra second would be split up into smaller units and added throughout the day as it will prevent the OS from meeting accuracy requirements.