Hi, We are planning to upgrade from postgres 9.5 to postgres 10, on centos version 6.8, We have a database of around 400GBs. We need to perform the upgrade activity with minimum downtime (around 1-2 hours). We are thinking of logical replication for the same. but The issue is we already have configured streaming replication on it (1 master and 2 slaves). So On master, we can upgrade the master by changing parameter wal_level to replica. but I need to know how will I upgrade the slave servers, so I am little confused for the approach for upgrade .
