In 3.x.x, Docker Edition was a licensed offering. So use of that software without a support contract transgressed the license. Another result was that because Ceva did not have any contract with Gluu, we did not have any record of a production deployment of 3.x using GKE.
Doing a 3.x to 4.x migration is never an in-place upgrade--not in VM's or K8. It always involves export/import.
To do this migration, we need to update our quote. Upgrade projects are a "project". It will require planning, testing and a cutover. This is outside of support.