Using the vSphere (Web) Client, it is only possible to "upgrade" your virtual hardware to the latest version supported by your ESX host. Sometimes, it's necessary to set the hardware version to a specific version, rather than just the latest supported one. This can be done through PowerCLI (for use with vCenter) or ESXi Shell (for free ESXi).

Before you begin, note that you have to power down a VM before you can change the hardware version.

You need VMWare vSphere PowerCLI installed on a computer, and access to a vCenter server (can be appliance or full version for Windows) with the necessary credentials.

Connect to the vSphere server:

$cred = Get-CredentialConnect-VIServer -Se  ...