Hi Nirbhay,
We're looking forward to these fixes:
https://mariadb.atlassian.net/browse/MDEV-5786 - We were previously running mysql_upgrade on every node and getting errors due to replication. We now disable replication while mysql_upgrade is running but this makes us vulnerable to writes while replication is disabled. We could prevent writes while replication is disabled, but we expect this fix will allow us to revert our automation around disabling replication.
https://mariadb.atlassian.net/browse/MDEV-6492 - Our understanding is that until we receive this fix, nodes can receive writes that may not be replicated while in donor mode for an rsync SST. We expect this fix to prevent writes while in donor mode for rsync SST.
Thank you,