The latest version of Prepar3D (or P3D) is out with mostly graphical updates and no, it’s not based on Unreal Engine.
The sim is still based on Microsoft ESP, the platform that powered FSX and it’s still compatible with that sim as well.
Unfortunately, it doesn’t seem like we are getting anything new for helicopters, which is a shame. We do have to keep in mind that we, the consumer market, are not really Lockheed Martin’s market. Don’t forget that, even with what is now called “Personal” license, which allows for the use of the sim at home, this is a product aimed at professionals and companies.
That means that it is usually customized for specific purposes and the flight dynamics are built to cater for a client’s needs. Therefore, Lockheed Martin seemed to have decided not to update the flight dynamics. And that’s a shame because it means helicopters in the sim are not really up to speed with other sims in the market.