With vSphere 5.1, Virtual Machine hardware version is referred as VM compatibility in vSphere Web Client. You can upgrade the VM compatibility from the older version to latest version that is VM hardware Version 9. In previous versions of vSphere, you need to get an decicated downtime to perform VM hardware upgrade.As of vSphere 5.1,You don’t need to get an downtime for the virtual machine to perform the virtual machine hardware version upgrade.

With vSphere 5.1, You have option to schedule the hardware upgrade. If it is scheduled, The hardware upgrade to the selected version will be done during the next reboot of the virtual machine. Even you have additional control to perform the VM hardware version upgrade only during the only during normal guest shutdown. So that, you can make sure VM hardware was not upgraded during VM down due to some other issues.

Steps to schedule a VM compatibility upgrade from vSphere Web Client

1. Login to your vCenter server using vSphere Web Client

2. Browse towards your virtual Machine in the inventory

3.Right-click your VM and click on All vCenter Actions

4. Click on Compatibility and select “Schedule VM compatibility Upgrade”

5. Select the Compatibility version from the drop-down list to upgrade to

6. Select the check mark “only upgrade after normal Guest OS shutdown”

7.Click ok to schedule the upgrade.

The above step can also be performed via Virtual Machine Edit settings

Right-Click the VM -> Edit settings ->Virtual Hardware -> Upgrade

VM hardware upgrade will be completed during the VM next reboot.

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