Upgrading the virtual hardware version of a virtual machine
From release to release, VMware has enhanced the functionality of virtual machines and each new set of capabilities is represented by a virtual hardware version number. Each virtual machine has an assigned virtual hardware number and this represents the feature set that the virtual machine can make use of and defines which version of host is required to run the virtual machine. In short, it's basically the file format of the virtual machine, since every virtual machine is made up of a definition file, virtual hard disks, and a few other special purpose files. In order for a virtual machine to make use of the new functionality, its virtual hardware must be upgraded.
Migrating virtual machines from one virtual hardware version to another is another common task during the life cycle of a virtual machine. You might need to add a type of hardware that only works with a virtual hardware version higher than you are running, or you might...
