WBS Gantt-Chart for Jira 9.13 supports Jira Server 7.6.0 - 8.5.x. See the version history page in Atlassian Marketplace for the latest supported version, though.
For platforms such as Java, database, OS, and browser, we support what is listed on Atlassian Jira's supported platform.
For details, please refer to the page of Supported platforms of Jira version you use.
If the magnification level of the display is other than 100%, the display layout may be distorted.