Regarding being potentially wide-open to exploits due to kernels being out of date, I would recommend installing ksplice uptrack (https://www.ksplice.com/ https

Regarding being potentially wide-open to exploits due to kernels being out of date, I would recommend installing ksplice uptrack (https://www.ksplice.com/ https://www.ksplice.com/). It allows you to apply kernel security updates without rebooting your machine. It's excellent, and I wouldn't consider running Ubuntu without it.