X-Plane 11, Will be compatible with X-Plane 12 for free.
Windows 7+, Mac OS 10.10+ or Linux 14.04 LTS or compatible, 64 bit mode
8Gb RAM / 3Gb VRAM Minimum, 16-24Gb+ RAM / 6Gb+ VRAM Recommended
Last version: 2.5.4 (29.10.2021)