While troubleshooting an issue generally post upgrade where UI is not starting up and you want to capture more information by Enabling the DEBUG on UI and Core. This article covers the steps to Enable DEBUG on Tomcat(UI) and Core Engine.
For Tomcat(UI), modify /opt/ConnectALL/UI/tomcat/webapps/ConnectAll/WEB-INF/classes/log4j2.xml to set DEBUG on below property.
For Core, modify /opt/ConnectALL/Core/conf/log4j2.xml and update the same property to DEBUG
Start connectall-broker, connectall-core, connectall-ui services. Let all services start and verify the respective logs have DEBUG statements being logged.