While the normative XMI file at
represents the UML 2.5 metamodel correctly, it contains two
sets of syntactical errors that will be corrected in UML 2.6.
A UML.xmi file with these corrections applied is provided here
as early access, please see the comment in this file for
further details: http://www.omg.org/spec/UML/2.5/Beta2/UML.xmi