Does not quite have the same significance as 31 December 1999, but I’m sure someone in the mainstream press will soon draw the parallels with Y2K with stories of Airliners getting lost or Trading systems failing due to timing errors, April 6th 2019 is the date when GPS systems reset !
Actually for the second time the week code broadcast as part of the GPS signal is resetting back to zero.
The GPS system uses 10 bits to store the GPS Week Numbers starting from 6th January 1980, so every 1,024 weeks (approximately every 20 years), the GPS Week Number rolls over from Week 1,023 to Week 0, this is known as a GPS Week Number Rollover. This has already occured on August 21, 1999 but that was before the explosion in the use of GPS is smartphones, drones, buses etc.
There are efforts happening across industry to make sure that disruption is minimised, but there may be issues with older GPS receivers and smartphones .
With modern connected devices firmware updates can be applied without to much effort, I remember because I’m had one Garmin and Magellan sending out RS-232 cables and CD-ROMS to update their receivers in 1999 !
In summary look out for firmware updates and “Don’t Panic !”