See:

https://github.com/cloudfoundry/cf-release/blob/master/templates/cf-release-template.yml.erb#L350
https://github.com/cloudfoundry/cf-release/blob/master/jobs/cloud_controller_ng/spec#L169

I don't know the implications of changing this without a migration path. Can we do this part as a separate pull request and think over the implications. Its nearly a good thing that it cant be changed cause it can't be migrated.