StarUML 2 2.8 was available to download from the developer's website when we last checked. We cannot confirm if there is a free download of this software available. The most popular versions of the software 2.8 and 2.1.4. This program was originally designed by MKLab. We recommend checking the downloaded files with any free antivirus.
From the developer:
A sophisticated software modeler. StarUML 2 is one of the most popular UML tools in the world. StarUML 2 is compatible with UML 2.x standard and supports totally 11 kinds of UML diagrams: Class, Object, Use Case, Component, Deployment, Composite Structure, Sequence, Communication, Statechart, Activity and Profile Diagram. You can easily find and install extensions via Extension Manager from official extension registry or Github repositories.
You may want to check out more software, such as WhiteStarUML, which might be related to StarUML 2.