One of our lasers is an older ULS M360. I had problems going from X15 to 2021.
We tried to install the legacy ULS color palette in CD2021 but some colors were not recognized by the driver software. After a lot of struggle, we had to build a new palette in 2021 that was an exact copy of the old one. There may be smarter ways to do it, but what we did was make a new document in 2021 with a bunch of little rectangles. Then we'd look at the old X5 palette and note the exact RGB values for each color, and assign those colors to the rectangles in the new document. When that was finished, we did "create palette from document" and used that new palette for all laser work on the ULS. It has worked great.
Also, you may need to confirm that your color management settings in 2021 are set to match what was working in 13.
Thank you vert much John,