interesting! the (1999) is a mix of old and new:

"This newly processed image comes from data originally captured by NASA’s Hubble Space Telescope in 1999 and 2000. The color assignments in this image have been matched to those used in the new 2024 data, providing a better comparison."

the original coloring (of the 1999-2000 image) is in the article, or also at https://science.nasa.gov/mission/hubble/science/explore-the-... with some other details

It's frankly hard to tell much difference when put into the same color scheme. Granted, those minute changes represent MASSIVE shifts in the arrangement of matter throughout the nebula, it just doesn't look that way from this far away.