Control Center 5.0 will support Firewall v8. CC 5.0 has not been released yet. I do not know the release date, however. It should be soon though.
Just came across this post. CC 5.0 was released in late June. The release notes are on mysupport.mcafee.com, search for PD22681.
Control Center v5 was released the end of June and is available on the McAfee Website with your Grant ID. v5 is a patch to v4.0.0.05 and does not require a re-image. We drastically overhauled the Control Center UI into a consolidated user interface. CC v5 manages v8 and is also backwards compatible to mange v7 firewalls so it should support your upgrade as you move from v7 to v8.