Microsoft Flight Simulator may be the oldest (the series is about to turn 40!), but flight sim competitor X-Plane has also been at it for decades. And yesterday a new version - X-Plane 12 - was released as early access.
So it's an early version that's still in development that's been released, and you have to be aware that mods and third-party stuff might not work. But X-Plane 11 is included as a backup, if that's any consolation. New in version 12 are, among other things, new planes, weather effects and improved graphics. The early access version currently contains 19 aircraft with detailed cockpits.