1. Proposed title of this feature request
Allow adding ipv6 VIPs to existing dual stack clusters

2. What is the nature and description of the request?
Request is to have the ability to add IPv6 for API and ingress to existing dual stack clusters, i.e. clusters that have been set up with a previous version of OCP where this hasn't been possible, but now it is, e.g. OCP 4.12

3. Why does the customer need this? (List the business requirements here)
Customer has set up OCP clusters with dual stack, however IPv6 was not set for API and Ingress, which was a known limitation at that time. Now with OCP 4.12, this limitation is overcome for new installed cluster, however not upgraded clusters.
So at the moment it seems the only way forward is to recreate the cluster which is not only not practical but also impossible for customers having a lot of clusters out there needing this and hence it is asked for the ability to add IPv6 IPs