TID 10094313 explains how to upgrade or apply service pack to a cluster
(procedure "2" is listed below)

Although it says "mixed environments are not supported", I'm not sure it
that refers to the version of Netware, or the service pack itself.

I have a 6 node cluster, and don't want to apply the SP5 to all 6 nodes
on the same day (it's currently sp3). I was planning to apply it to one,
let it join back to the cluster, and see how it goes for a week or so,
then do the others.

Is this acceptable? I can't find any mention of this being an issue in
either the patch readme or the cluster services documentation.

1. Determine which nodes to upgrade in this iteration of the overall

2. Migrate resources to node(s) NOT being upgraded at this time.

3. Issue a CLUSTER LEAVE on node(s) being patched.

4. Apply the Support Pack to the node(s) out of the cluster. When it
completes, it will reboot and re-join the cluster.

5. Repeat this process for nodes that remain un-patched.