So far as the process went for remastering the cgi effects the 2K effects were printed out to 35mm film and then scanned at 4K…
Interesting way to do the remaster and blend better… The actual quality of the image looks great too from a few screen shots of the remaster but I have heard it has some different color grading choices but it was done by the original colorist and supervised by Peter Jackson.
Not heard of anything being changed though or tinkering so far as replacing anything ot altering something new effects say for instance.
Will be interesting to know how it will be but I have to say looks good from the screenshots the remaster.