It's supported by the protocol. But I'm not sure if it's actually supported by anyone who deployed the protocol. It requires to actually support connection ID migration in the library (which not all of them do), as well as to support it on infrastructure (e.g. L4 load balancers): If those receive a packet belonging to the same connection, but having a new source IP address (due to client having migrated), they still need to route things to the same server which has all the state about the connection. Therefore the whole thing is rather hard to implement.