Rumor seems to be that when Nikon moves to mirrorless bodies current lenses would not be compatible, although maybe? there might be some kind of converter so these lenses could be used. The question, which I have not seen addressed, is why anyone would buy a Nikon mirrorless if their current lenses were not compatible and a converter to facilitate migration were not available. There are excellent manufacturers (Sony for example) that have been producing mirrorless systems for years and have probably gotten most of the bugs and idiosyncracies out, while Nikon does not have long experience with the technology.