-vparameter to get more detailed output.
DataVersionMismatch: OS Migrate runtime is version 'X.Y.Z', but tried to parse data file 'abc.yml' with os_migrate_version field set to 'A.B.C'. (Exported data is not guaranteed to be compatible across versions. After upgrading OS Migrate, make sure to remove the old YAML exports from the data directory.)
When OS Migrate export playbooks run, the existing data files aren’t automatically truncated. OS Migrate gradually adds each resource serialization to the (perhaps existing) YAML file, or it updates a resource serialization if one with the same ID is already present in the file.
OS Migrate will refuse to parse YAML files which were created with a different version. In many cases such parsing would “just work”, but not always, so OS Migrate is being defensive and requires clearing out the data directory when upgrading to a new version, and re-running the export playbooks.
Alternatively, an advanced user can verify that the previous and new OS Migrate does not include any change in export data structures, and can edit the
os_migrate_versionfield in the data files. This option should be used with caution, but it may prove useful in special scenarios, e.g. if external causes prevent re-exporting the data.