There is no way to update the agent machines across multiple core machines at the same time using the central console. However, it is possible with the central console to manage each core one at a time and do a push installation of the agent software. To do this, choose the core you want to manage -> on any page click the dropdown arrow next to the word "Protect" -> Select "Deploy Agent Software" -> follow the wizard and choose to deploy using "local core" so that it picks up the agents that already exist on the core. Please remember that each agent must be rebooted after the installation before a successful backup can be taken. You can choose to have the software automatically reboot after upgrade or you can disable that feature and manually do it.