Several groups are reporting an upcoming event with the GPS satellites that may affect certain software that gets date and time information from the satellites. A ten-bit counter used within the satellite protocols holds the GPS Week Number. This counter increments by one for every week in operation, which means that the counter can only count 1024 weeks before the number “rolls over” to zero. The next rollover event will occur on April 6, 2019, at which time the counter will roll from 1023 back to 0. Most modern software handles this properly, but some software could handle it incorrectly. The report linked below from the Department of Homeland Security provides some additional information.