Hi Tom, sorry for not replying sooner.
Draken 5.1 (released in 2021) is optimized for Prepar3D v5. If you have not already updated your version of Draken to version 5.1 you can download the free update from the webshop. You need to log in with the same account that you used when you purchased Draken. Please let me know if you have any trouble with the update.
Regards /Thomas