Not that long ago, I completed my eighteenth Trek novel, currently scheduled as a January 2018 release, meaning that it will be out at the end of December this year.
DRG III made no further info available as of this posting, but as I speculated earlier there is a chance that this will be a novel called Original Sin, dealing with the U.S.S. Robinson in the Gamma Quadrant.
Curiously the listing for Original Sin has vanished from Simon and Schuster's website just when David confirms he has written a Star Trek novel for the date listed for Original Sin. If that has any further meaning or is just due to updating the listing with further information soon is not clear at the moment.