I'd love too, but no. But I have a close friend that works in their SRE team. I also meet lots of Spotify people at meetups and such as I live in Stockholm.
My guess would be that they will not migrate their data-related machines (Postgres, Cassandra etc) as the reason for going to Ubuntu is partially for Docker and using Docker in their testing and staging environments (to begin with).
The other one being that they don't have anyone maintaining an patched inhouse kernel for debian anymore (or they don't want to do that).
