Tony wrote:
Is it possible to ... backup Openstack with version "X" and restore to different fresh deployment of the same version
Yes, this is definitely possible. I know some users of Kolla-Ansible migrated their manual and other-deployment-tool-deployed OpenStack-based clouds to use Kolla-Ansible. This is certainly possible using the same version of services. All the data is captured in the sql database (usually mysql). Apart from custom config, this is the most important part to keep backed up (and obviously your users' data in store :-) ).
Please read the following great (opinion mine) blog post by Pierre Riteau from StackHPC, that nicely summarizes steps required for such migration: https://www.stackhpc.com/migrating-to-kolla.html
-yoctozepto