rinn Basically, there is no problem opening a Spine project created with an older version of the editor in a newer editor. However, the rotation behavior has changed since 4.0 because it is now possible to input rotation values greater than 360 degrees, so there is a possibility that animations created in 3.8 will behave differently in 4.1.19. Otherwise, there should be almost no problem.

Please refer to the Spine User Guide for notes on updating editor versions for more information:
http://esotericsoftware.com/spine-versioning#Synchronizing-versions

rinn Yes, bones and meshes settings should be loaded correctly. Please let us know if you run into any trouble.