The Japanese website SankeiBiz reported some info about the future Nikon high end camera:
– Development of the new mirrorless is advancing rapidly
– Goal is to release the camera within the current fiscal year (which means til March 2019).
– It will probably be shown at a large-scale overseas exhibition (I guess this means Photokina in September)
Within the same article they also confirm that Canon wants to become number one in the mirrorless market too.