vSphere 6.5 Update 1 supports migration from vSphere 6.0 Update 3 and vSphere 5.5 Update 3b, and it can be performed in different ways.
The simplest method that you can use to upgrade your infrastructure is through vSphere Update Manager (VUM), a tool that centralizes and simplifies the management of patches and updates for the VMs, ESXI hosts, and vApps installed in the virtual environment.
The components of the vSphere platform can also be upgraded through scripts, using CLI commands that allow for the automation of the installation procedure, making the process faster overall.
Before migrating your infrastructure, keep in mind that vCenter Server must be running version 6.5 Update 1 before upgrading the ESXI hosts to 6.5 Update 1.