Each workflow is the recommended upgrade path while upgrading your vCenter Server 6.5 and 6.7 environment, that contains one or more host profiles with version 6.0, 6.5 and 6.7.

Upgrade Support Matrix

When you upgrade your vCenter Server from version 6.5 or 6.7 to version 7.0, you can keep your current ESXi host version and Host Profiles version. For other upgrade workflows, see the Upgrade Support Matrix.
Note: vCenter Server version 6.0 and ESXi 5.5 hosts are not supported in vCenter Server 7.0. You can use the Recommended Host Profiles Upgrade Workflows in the vSphere Host Profiles 6.7 guide as intermediate upgrade steps.
Table 1. Upgrade Support Matrix
Upgrade Workflow vCenter Server ESXi host Host Profiles
earlier than 5.5 -> 6.0 / 6.5 -> 6.7 Requires an upgrade Requires an upgrade Requires an upgrade
5.5 -> 6.7 Requires an upgrade Requires an upgrade Requires an upgrade
6.0 -> 6.7 Requires an upgrade An optional upgrade An optional upgrade
6.5 -> 7.0 Requires an upgrade An optional upgrade An optional upgrade
6.7 -> 7.0 Requires an upgrade An optional upgrade An optional upgrade
earlier than 6.5 -> 6.5 / 6.7 -> 7.0 Requires an upgrade Requires an upgrade Requires an upgrade
6.5/6.7/7.0 →7.0 Update 3 Requires an upgrade An optional upgrade
Note: You might need to keep a 7.0 GA host if you want to validate or edit a 7.0 GA host profile.
An optional upgrade

vCenter Server and ESXi Version Interoperability

Starting with vSphere 7.0 Update 3, a major-version vCenter Server instance supports any ESXi Update release version of the corresponding major release. That is, a vCenter Server 7.0 Update 3 instance can manage ESXi 6.5, ESXi 6.7, and any Update release of ESXi 7.0.

So, you must upgrade vCenter Server to 7.0 Update 3, if you want to manage ESXi hosts of version 7.0 Update 3 or a later Update release. You must also upgrade vCenter Server to version 7.0 Update 3 if you want to manage a mixed environment of hosts of any ESXi 7.0 Update release version, for example 7.0 GA, 7.0 Update 1, or 7.0 Update 2.