The agent plug-ins are not being upgraded or installed after migrating from one Notification Server to a new Notification Server.
ITMS 8.7
Do the following for all of the plug-in Install and Upgrade policies.
For example, in the SMP Console go to the Software Update Plug-in Policy. You will see the following:
Change the Schedule (in yellow above) from "Run Once ASAP" to "By Schedule" and add two Schedules. Add the first by time don't edit it. Add the second by window, check once per hour, and repeat daily. Enable the policy and Save the changes.
When you are finished it will look like this: