How can I kill user sessions where last request is more than say 8 hrs?

When I look in my list of User sessions , I see many sessions where last request is several days ago.
What is the best way to kill/remove these ‘old’ user sessions ?

You could write a cron job that checks hourly/daily if sessions are still open. There is the io.jmix.audit.UserSessions that has an invalidate method. And with userSessions.sessions() you get the currently active sessions.

Try this

In my config:

server.session.timeout=180 # 3 hours
vaadin.servlet.close-idle-sessions=true