Red Hat Virtualization 4.3 and later does not support 4.0 cluster compatibility version or data center compatibility version. So when you upgrade from Red Hat Virtualization 4.0, you must update the cluster and data center compatibility versions to at least 4.1 before you upgrade the Manager from 4.2 to 4.3. Then, if you want to use the 4.3 compatibility version, update the compatibility versions again after completing the Manager upgrades.

You must also update the hosts before updating the compatibility versions, but only need to do so once. The host repositories stay the same across Red Hat Virtualization versions, so the hosts will already be upgraded to the latest version after a single update.

Upgrading your environment from 4.0 to 4.3 involves the following steps: