Schedule agent upgrade

We have a subset of computers that are protected by DeepFreeze. We have worked out a monthly schedule with the I.T. manager to automatically thaw these machines so that Desktop Central has an opportunity to scan and deploy updates. This works very well. However, the problem we have is that whenever we upgrade Desktop Central itself, it then requires the remote agents to also be upgraded. We therefore need to ability to schedule the remote agent upgrade during a specific time just like we do with software updates. Currently DC attempts to upgrade the agents "whenever it feels like it", so these machines protected by Deep Freeze never get the new agents. Can someone please tell us how to schedule the remote agent upgrades after a DC server upgrade?

Thanks!