We have already shared a preparation sequence for an upgrade. Step 5 in the process is to upgrade Foundation.
The upgrade process for the Foundation is straightforward and does not require any downtime:
Run NCC as described in Run NCC Checks.
Log on to the Prism Web Console, click the gear icon in the main menu, select Upgrade Software in the Settings page, and then click the Foundation tab.
If an update is available, click Upgrade Available and then click Download.
When the download is complete, click Upgrade > Upgrade Now, then click Yes to confirm.
To run the pre-upgrade installation checks only on the Controller VM where you are logged on, click Upgrade > Pre-upgrade. These checks also run as part of the upgrade procedure.
The Upgrade Software dialog box shows the progress of your selection, including pre-installation checks.
To upgrade the Foundation of the cluster at a dark site please follow the steps provided in the Prism Web Console Guide v5.10: Upgrading Foundation
Further on the subject of upgrades: