Rhino File Compatibility Guide
Which Rhino versions can open which .3dm files? The complete compatibility matrix, explained.
The compatibility rule
Rhino can always open files from older versions, and can Save As one or two versions back. It can never open files from newer versions. Rhino 8 reads everything; Rhino 5 reads only Rhino 5 files and older.
What changes between formats
Rhino 6 introduced new annotation styles. Rhino 7 added SubD geometry. Rhino 8 reworked materials and annotations again. When downgrading, newer features are translated to their closest older equivalent — SubD becomes a mesh or NURBS in pre-7 formats, for example.
Best practices for teams
Agree on a common working version for shared projects, keep a master file in the newest format, and downgrade copies for collaborators on older releases. RhinoFileConverter makes the downgrade step a 10-second job.