Install or upgrade to the Lotus Domino 6 Enterprise server or the Lotus Domino 6 Utility server. These servers enables you to set up a Domino 6 cluster.
Note You can include the following Domino servers in a cluster: the Domino Release 5 Enterprise server, the Domino Release 4.62 Enterprise server, the Domino Release 4.6 Advanced Services server, and the Domino Release 4.5 Advanced Services server. However, these servers will not have access to the features that are new in Domino 6.