[panick21_]

seL4 is still being worked on. There are recent changes to the wat time is tracked. I would say in terms of research seL4 is still up there. The current trend is very much on verification of user space and also verification chains down to RISC-V.

[wittystick]

Probably the biggest development in seL4 since this is the MCS (mixed criticality systems) addition, which provides capabilities for budgeting CPU usage to give guarantees for components that need higher priority. There's some videos by Gernot Heiser on YouTube covering it.