@LSinNY I went from JSS 9.97 on Ubuntu 12.04 with Java 1.7.0_121, Tomcat 7.0.52 and MySQL 5.5.54 to JSS 9.98 on Ubuntu 16.0.4 with Java 1.8, MySQL 5.7.x and Tomcat 8.0.x without any problems. A tech from Jamf Support said it was ok to do and pointed me here for information on how to do it. The only mistake I made was forgetting to modify the DataBase.xml file before starting things. I use the manual install process so I needed to edit some files and simply forgot to edit the DataBase.xml file. Otherwise the process went very smoothly and worked fine. I would encourage you to do this on a test environment before you do it on your production system.