The Sipwise C5 has the ability to mark a pending reboot for any server, using the file /var/run/reboot-required. As soon as the file exists, several components will report about a pending reboot to the end-user. The following components report about a pending reboot right now: ngcp-status, ngcpcfg status, motd, ngcp-upgrade. Also, ngcp-upgrade will NOT allow proceeding with an upgrade if it notices a pending reboot. It might affect rtpengine dkms module building if there is a pending reboot requested by a newly installed kernel, etc.