upgrade to without downtime

During managing customer that use Column Store Cluster and in Single Mode, there is a huge operation need to be able to upgrade to major release without Downtime. This is also a important case for Rollback, as for customer request.

Sometime customer provide new servers that could be used during the operation, but considering that CS do not use binglogs , how can we :

1- set up a new cluster
2- get the OLD VERSION data to the new cluster
3- start to have the sync data from the beginning the operation to live traffic
4- keep have the same write on the old and on the new cluster

With single node customer also would like to have minor upd without downtime