After upgrading to ITMS 8.6, Task Server is listed as "pending reboot". However, the Task Server has been already rebooted after upgrading the Task Server plug-in.
Please refer to the ITMS 8.6 Release Notes. under "What's New in This Release".
It mentions the following change:
Also, the computer that has a pending reboot, is being marked in the SMP Console. The new status "Pending reboot" is produced to extend the state details of the Task Servers and their clients.
The main goal is intended to draw attention to the Task Server computers requiring reboot in case the clients are unable to register within it.