Each new version of vSphere includes some improvements and new features and many of them will be applied on virtual machines. The improvements and features will be add to “Hardware Version” and you be able to use those, if you use latest “Hardware Version”.
It’s strongly recommended that don’t upgrade your hardware version to latest just when you need to use a specific feature or expand hardware resources that older hardware version doesn’t support that.
Because “Hardware Version” doesn’t have any compatibility with older ESXi and if you have mixed cluster, you can’t use latest hardware version.
Here is an example:
You have a cluster and the cluster contains some ESXi 6.5, 6.0 and 5.5. If you upgrade hardware version to 11, your virtual machine will be hosted by ESXi 6.0, ESXi 6.5 and the machine will not be migrated on ESXi 5.5.
So, keep your hardware version compatible with oldest ESXi in your environment. You can downgrade hardware version but it’s not recommended.
For make sure about hardware version, you can change default version on your cluster anytime.
Let’s review new hardware version, compare it with older versions and compatibility with ESXi: