In the official announcement, it was confirmed this update would include ray-traced shadows, reflections and audio, and that it would be entirely free for all existing owners of the game.
Here's a brief rundown about what to expect, for those who haven't played it before (via the Microsoft Store):
"Deliver Us The Moon is a Sci-Fi thriller set in an apocalyptic near future, where Earth's natural resources are depleted. A lunar colony providing a vital supply of energy has gone silent. A lone astronaut is sent to the moon on a critical mission to save humanity from extinction. Will you save mankind or be forgotten in the dark abyss of Space?"
Will you be checking this upgrade out when it launches on Xbox Series X|S later this year? Tell us below.