[Question posted by a user on YugabyteDB Community Slack]
Is it possible to have the primary data cluster and read replica be at different versions? primary data @ 2.1 and replicate cluster @ 2.8
Ideally, no. During software upgrades, temporarily different nodes can be on different releases. But in a steady state, the read-replica nodes should be the same version as the primary cluster.
With xCluster, where the two clusters are really independent clusters linked with an async replication channel, they can be on different releases for extended periods of time.