The GPS system itself basically ignores leap seconds, and has been slowly drifting out of sync with solar time. They were 15 seconds fast before the change, and are now 16 seconds fast.
The GPS signal includes the current offset between GPS time and UTC
. That number (only) just went from 15 to 16.
You don't actually need to know the correct time for GPS to work, you just need to have the same time as the satellites do. In fact, almost no GPS receivers actually know that time (it would require a rather expensive and large atomic clock to stay sufficiently close over any reasonable period of time), rather the GPS receiver solves for the time as part of the process of determining the position. In a very simplified sense, the GPS has receiver has four unknown variables (its X, Y and Z coordinates and the time), and four equations (basically it can write an equation for the distance to each of the four satellites its tracking). So four equations and four unknowns, and you can solve for your three dimensional position and the current time. If a GPS receiver actually knew the current time with sufficient accuracy, it would need only three satellites to produce a three dimensional fix. Obviously real GPSs can make use of more than four satellites to get a better position.
But the GPS/UTC
time offset is not really used, it's mainly just passed out to the systems using the output of the GPS receiver (for example, you'd expect that to be used by the time display on the GPS). Obviously any systems that mishandle the change in the offset may have problems, but the GPS system (and the receivers themselves - at least the parts that determine the current position and time), are not going to be affected.