Aircraft developer FlightFactor has confirmed that a number of their released aircraft will be compatible with X-Plane 12 when the simulator launches later this year.
On a post over on X-Plane.org, the team confirmed that they have tested a number of aircraft extensively with the new platform. The aircraft tested and that will be compatible at the launch is the Boeing 757/767 series and also the A350.
FlightFactor also confirmed that they will support X-Plane 12 in the future when updates or new features are added to the simulator.
It’s not made explicitly clear in the post if the aircraft will need an update or if they just ‘work’ when in X-Plane 12. Nor is it made super clear if you will need to buy an upgrade license or anything of the sort. However, ramzzess did say “[I] Hope this puts your mind at ease and you can feel free to purchase those models now,” indicating that current owners will be able to use the planes in X-Plane 12.