Hosts might contain third-party software, such as Cisco Nexus 1000V VEMs or EMC PowerPath modules. When you upgrade an ESXi 6.5 or ESXi 6.7 host to ESXi 7.0, all supported custom VIBs are migrated and remain intact, regardless of whether the VIBs are included in the installer ISO.
If the host or the installer ISO image contains a VIB that creates a conflict and prevents the upgrade, an error message identifies the VIB that creates the conflict.
To discover potential problems with third-party software before an upgrade operation, scan the hosts against an upgrade baseline and review the scan messages in the vSphere Lifecycle Manager compliance view. See Host Upgrade Compliance Messages and Host Upgrade Compliance Messages When Cisco Nexus 1000V Is Present.
For information about upgrading with third-party customization, see the VMware ESXi Upgrade documentation.
For information about using vSphere ESXi Image Builder to make a custom ISO, see the VMware ESXi Installation and Setup documentation.