A backup taken from the cluster, contains the configuration for all nodes in the cluster.
So if you take a backup from mwgA (which has mwgB as a partner), the backup will be able to restore on mwgA and mwgB.
Yes an older backup can be imported on a newer version. Coversley, a newer backup cannot be imported on a older installation.
The steps for upgrading a cluster is outlined here:
Take note, taking the backup happens before removing all the nodes from the cluster.
Thank you Jon,
Thanks for your information,
With the best !