Hi! It is an official sequel, although it falls more into the anthology series category.
I was involved in the creation of the first three chapters as an artist, along with another development team (Imdemmi). After a while, I created this other studio, as well as this sequel.
Of course, I asked for permission to continue the series, and everything went smoothly. In fact, I still talk to the original developers, but imdemmi is on hold.