Subscriptions at federated level

I am currently a GraphQL data engineer working for Block. From what I understand GraphQL subscriptions cannot be handled at the federation level and must be handled at the subgraph level. We would like to implement subscriptions at the federated level to increase security as our subgraphs are private. We understand that it is Apollo’s intention to support subscriptions at the federated level in the future and my team and I were wondering how far along that feature is and what we can do to help.