i was going through the forum looking for any option that can help me and i found this code to convert a json file from one version to another. I wanted to know if there is an equivalent for .skel files, apparently it is easier.
Spine -u 3.6.53 -i skeleton-3.6.json -o skeleton.spine
Spine -u 3.8.93 -i skeleton.spine -o skeleton-3.8.json -e export-settings.json