RHV 4.2.8 requires EAP 7.2, but unfortunately EAP made a backward incompatible change, so EAP 7.2 is no longer included in jb-eap-7-for-rhel-7-server-rpms channel, but RHV administrators needs to subscribe jb-eap-7.2-for-rhel-7-server-rpms to be able to upgrade from 4.1/4.2.z to 4.2.8 or install new 4.2.8.
Updated documents on Customer Portal: Installation guide https://access.redhat.com/documentation/en-us/red_hat_virtualization/4.2/html-single/installation_guide/index#Enabling_the_Red_Hat_Virtualization_Manager_Repositories_standalone_install Upgrade guide: https://access.redhat.com/documentation/en-us/red_hat_virtualization/4.2/html-single/upgrade_guide/#Upgrading_the_Manager_to_4-2_3-6_local_db Java SDK (not essential, but might as well update at same time): https://access.redhat.com/documentation/en-us/red_hat_virtualization/4.2/html-single/java_sdk_guide/ Release notes section for 4.2.7: https://access.redhat.com/documentation/en-us/red_hat_virtualization/4.2/html-single/release_notes/#release_notes_4
Published documents: https://access.redhat.com/documentation/en-us/red_hat_virtualization/4.2/html-single/installation_guide https://access.redhat.com/documentation/en-us/red_hat_virtualization/4.2/html-single/upgrade_guide/ https://access.redhat.com/documentation/en-us/red_hat_virtualization/4.2/html-single/self-hosted_engine_guide/ https://access.redhat.com/documentation/en-us/red_hat_virtualization/4.2/html-single/release_notes/ https://access.redhat.com/documentation/en-us/red_hat_virtualization/4.2/html-single/java_sdk_guide/index#Prerequisites