While 2025 works for most paths, some low-level ARX loaders require the R format ( R25.0 ). Always test both.
Another trace appears in a 2016 project ( pyacad ) where the author overrode environment variables in the subprocess call: autodesk autocad --env.acad release name-
Understanding --env.acad (actually the ACAD environment variable) and AutoCAD’s internal release naming saves you hours of debugging and helps write robust automation. Whether you're managing deployments, developing plugins, or just curious, keep this reference handy. While 2025 works for most paths, some low-level