as shards will not be replicated from the more recent version to the older version.
Rolling upgrade | Elasticsearch Guide [8.11] | Elastic
explains why the node is on the newer version and not getting replication.
I have ran upgrade all other nodes following the rolling upgrade process here: Rolling upgrade | Elasticsearch Guide [8.11] | Elastic
and everything has turned a pretty shade of Green!
Thanks for taking the time to answer my questions and help!
S