To successfully export a Spine 4.2 project for use with the Unity runtime 4.1, you need to ensure that the versions of the Spine editor and the spine-unity runtime match. The JSON or binary files exported from Spine 4.2 are not compatible with the spine-unity 4.1 runtime. You should re-export your project using Spine 4.1 to ensure compatibility. If you have already created your project in Spine 4.2, you will need to open it in Spine 4.1 and export it from there. This process may involve some data loss if features used in 4.2 are not available in 4.1. Additionally, using the Spine JsonRollback tool to downgrade from 4.2 to 3.8 is not recommended for runtime use, as it is primarily for downgrading projects for use in older Spine editor versions.
