Thanks @ggalmazor and team!
A new update; I have now been able setup Aggregate 2.0.3 on a Centos 7 tomcat 8 server running Postgres 9.2. I had one error (see below) that I had to edit the server.xml file in Tomcat to make Aggregate work.
17-May-2019 21:35:33.454 WARNING [https-jsse-nio-8446-exec-7] org.apache.catalina.loader.WebappClassLoaderBase.clearReferencesJdbc The web application [ODKAggregate] registered the JDBC driver [org.postgresql.Driver] but failed to unregister it when the web application was stopped. To prevent a memory leak, the JDBC Driver has been forcibly unregistered.
A bit of research online indicates this error shows it could be related to Aggregate. I hope this helps to make the app better.