Jim Dalrymple writing at the Loop:
Apple introduced a new Photos app during its Worldwide Developers Conference that will become the new platform for the company. As part of the transition, Apple told me today that they will no longer be developing its professional photography application, Aperture.
Hopefully this is a move for the better. Both iPhoto and Aperture libraries will migrate to Photos.
[Originally I wondered what would happen if you had both but they use the same database.]