Many environments have already adopted some level of virtualization. A data center design will likely have to include upgrading the current infrastructure to leverage new features and functionality. Upgrading ESXi is a simple process, but it requires some planning to ensure compatibility and supportability. Chapter 4, vSphere Management Design, provides details about upgrading vCenter Server. This recipe will provide the details for planning an upgrade of ESXi hosts.
ESXi 5.x can be upgraded directly to ESXi 6.0 or 6.5. If you want to upgrade a host to 6.7 from 5.x, you'll first need an upgrade to 6.0 or 6.5, then another upgrade to 6.7.