NB! Symantec does not recommend upgrading the Symantec Management Agent and the software update plug-in to 8.6 (and later) and applying scheduled software update policies during a single maintenance window. While this combination of upgrade and update installation in one maintenance window is possible, the main risk is as follows:
The best practice is to upgrade the Symantec Management Agent and the software update plug-in, and then in a maintenance window, apply scheduled software update policies.
However, if you still need to perform all these activities during one maintenance window, because the maintenance window opens rarely (e.g., once a month) and lasts for a short period of time (e.g., 8 hours), follow the steps described in this article.
As soon as the maintenance window opens, the following processes occur in order: