The latest news about StarUML
XMI (XML Metadata Interchange) extension is available in Extension Registry. It allows you to export to XMI format and import from XMI file which exported by other modeling tools. It supports XMI version 2.1 and based on UML 2.0 metamodel. This extension is open source and hosted on Github (https://github.com/staruml/XMI) under MIT License.