MagicDraw allows export to/import from UML models from/to MOF (both CMOF and EMOF) XMI files. MOF 2.0 and 2.4 (MOF 2.4.1 to be more specific) are supported.
For more information about the MOF domain model, see Meta Object Facility (MOF) Core Specification for MOF 2.0 or MOF 2.4.1.