The pre-migration step includes a plan of the tasks that should be done before starting the actual migration. An analysis of the expected benefits of the new features should be done to determine the added value to your business and justify the investment to management. Try to obtain as much documentation as you can, such as guides, release notes, and tips of the new release, to limit possible problems with the upgrade. Explaining how the new release and new features should be implemented and configured is also an essential point for a successful migration.

Make sure that running programs in the current vSphere environment are also supported in the release you are going to install. If other VMware products are used in your network, validate the compatibility of each product by using the VMware Product Interoperability Matrices that are available on the VMware website at the following URL: https://www.vmware.com/resources/compatibility/sim/interop_matrix.php.

Performing a health assessment for your current vSphere environment is useful for detecting objects that are no longer needed but are still consuming resources. They also help fix misconfigurations to avoid issues during migration and network cleanup.
There are several tools available on the market that allow you to perform a healthcheck on the vSphere environment. In addition to solutions that require a license, some free tools can also be used to health check your virtual platform.

The following are some examples of commercial and free products that you can use to health check your environment:

• Licensed: VMware vRealize Operations Manager, vSphere Optimization Assessment (VOA), Runecast Analyzer, or Opvizor Health Analyzer
• Free: Turbonomic Virtual Health Monitor, Veeam ONE Free Edition, or RVTools