New mod was released on May 18, 2019:
"The Longest Journey HD is a mod for one of the best adventure games ever made. It includes neural network upscaled backgrounds and sprites, redrawn user interface and a lot of other small improvements thanks to ResidualVM implementation of the game engine. I wouldn't call it the final release, rather version 1.0. There is always room for improvement, because SISR algorithms are not perfect and the quality of the original graphics assets is not consistent. Anyway, future updates (if any) will be mostly cosmetic, nothing significant. Enjoy the game! P. S. Special thanks to bgK for his extensive support and assistance."
I haven't tried it myself yet, please share your experience if you do.