Hello,
The latest version of the Jasperserver is 9.0. To upgrade your 6.3 Japserserver to 9.0, please refer to the section "Upgrading JasperReports Server 6.4.x or Earlier" on page 51 of the below Upgrade guide for more details.
https://docs.tibco.com/pub/js-jrs/9.0.0/doc/pdf/js-jrs_9.0.0_upgrade-guide.pdf?id=1