All servers in a cluster must run one of the following: the Lotus Domino 7 Enterprise server, the Lotus Domino 7 Utility server the Lotus Domino 6.5 or Lotus Domino 6 Enterprise server, the Lotus Domino 6.5 or Lotus Domino 6 Utility server, or the Domino Release 5 Enterprise server.
Note Earlier releases of Domino do not have access to features that are new in Domino 7 or later.