Virtual Machine Compatibility

When you create a virtual machine or upgrade an existing virtual machine, you use the virtual machine compatibility setting to select the ESXi host versions that the virtual machine can run on.

The compatibility setting determines the virtual hardware available to the virtual machine, which corresponds to the physical hardware available on the host. Virtual hardware includes BIOS and EFI, available virtual PCI slots, maximum number of CPUs, maximum memory configuration, and other characteristics. New virtual hardware capabilities are typically released once a year with major or minor releases of vSphere.

Each virtual machine compatibility level supports at least five major or minor vSphere releases. For example, a virtual machine with ESXi 3.5 and later compatibility can run on ESXi 3.5, ESXi 4.0, ESXi 4.1, ESXi 5.0, ESXi 5.1, ESXi 5.5, ESXi 6.0, and ESXi 6.5.

Table 1. Virtual Machine Compatibility Options
Compatibility	Description
ESXi 6.5 and later	This virtual machine (hardware version 13) is compatible with ESXi 6.5.
ESXi 6.0 and later	This virtual machine (hardware version 11) is compatible with ESXi 6.0, and ESXi 6.5.
ESXi 5.5 and later	This virtual machine (hardware version 10) is compatible with ESXi 5.5, ESXi 6.0, and ESXi 6.5.
ESXi 5.1 and later	This virtual machine (hardware version 9) is compatible with ESXi 5.1, ESXi 5.5, ESXi 6.0, and ESXi 6.5.
ESXi 5.0 and later	This virtual machine (hardware version 8) is compatible with ESXi 5.0, ESXi 5.1, ESXi 5.5, ESXi 6.0, and ESXi 6.5.
ESX/ESXi 4.0 and later	This virtual machine (hardware version 7) is compatible with ESX/ ESXi 4.0, ESX/ ESXi 4.1, ESXi 5.0, ESXi 5.1, ESXi 5.5, ESXi 6.0, and ESXi 6.5.
ESX/ESXi 3.5 and later	This virtual machine (hardware version 4) is compatible with ESX/ESXi 3.5, ESX/ ESXi 4.0, ESX/ ESXi 4.1, ESXi 5.1, ESXi 5.5, ESXi 6.0, and ESXi 6.5. It is also compatible with VMware Server 1.0 and later. ESXi 5.0 does not allow creation of virtual machines with ESX/ESXi 3.5 and later compatibility, but you can run such virtual machines if they were created on a host with different compatibility.
ESX Server 2.x and later	This virtual machine (hardware version 3) is compatible with ESX Server 2.x, ESX/ESXi 3.5, ESX/ESXi 4.x, and ESXi 5.0. You cannot create, edit, turn on, clone, or migrate virtual machines with ESX Server 2.x compatibility. You can only register or upgrade them.

The compatibility setting that appears in the Compatible with drop-down menu is the default for the virtual machine that you are creating. The following factors determine the default virtual machine compatibility:

The ESXi host version on which the virtual machine is created.
The inventory object that the default virtual machine compatibility is set on, including a host, cluster, or datacenter.

You can accept the default compatibility or select a different setting. It is not always necessary to select the latest ESXi host version. Selecting an earlier version can provide greater flexibility and is useful in the following situations:

To standardize testing and deployment in your virtual environment.
If you do not need the capabilities of the latest host version.
To maintain compatibility with older hosts.

When you create a virtual machine, consider the environment that the virtual machine will run in and weigh the benefits of different compatibility strategies. Consider your options for these scenarios, which demonstrate the flexibility inherent with each virtual machine compatibility selection.

Objects in Environment	Compatibility	Results
Cluster with ESXi 5.5, ESXi 6.0, and ESXi 6.5 hosts	ESXi 5.5 and later	Preserves the ability of the virtual machine to run on other hosts in the cluster, such as ESXi 5.5. You might not have access to the latest virtual hardware features.
Cluster with ESXi 5.5, ESXi 6.0, and ESXi 6.5 hosts	ESXi 6.0 and later	Gives you access to virtual hardware features that are not available with ESXi 5.5. You cannot migrate this virtual machine to an ESXi 5.5 host. This virtual machine does not have all the capabilities available to virtual machines that run on ESXi 6.5, for example, you cannot configure a virtual machine to use 256 virtual CPUs.
Cluster with ESXi 5.5, ESXi 6.0, and ESXi 6.5 hosts	ESXi 6.5 and later	Provides access to the latest virtual hardware features, but cannot run on ESXi 5.5 or ESXi 6.0.

Objects in Environment

Compatibility

Results

Cluster with ESXi 5.5, ESXi 6.0, and ESXi 6.5 hosts

ESXi 5.5 and later

Preserves the ability of the virtual machine to run on other hosts in the cluster, such as ESXi 5.5.

You might not have access to the latest virtual hardware features.

Cluster with ESXi 5.5, ESXi 6.0, and ESXi 6.5 hosts

ESXi 6.0 and later

Gives you access to virtual hardware features that are not available with ESXi 5.5.

You cannot migrate this virtual machine to an ESXi 5.5 host.
This virtual machine does not have all the capabilities available to virtual machines that run on ESXi 6.5, for example, you cannot configure a virtual machine to use 256 virtual CPUs.

Cluster with ESXi 5.5, ESXi 6.0, and ESXi 6.5 hosts

ESXi 6.5 and later

Provides access to the latest virtual hardware features, but cannot run on ESXi 5.5 or ESXi 6.0.