All three upgrade approaches are able to handle the addition and deletion of new attributes and services automatically. Understanding the way this works will help explain how the upgrade mechanisms work in general.
AM Upgrade (LDAP)
In the case of the LDAP upgrade, the UpgradeServiceSchemaStep will determine whether there are additions or deletions automatically during update. These are processed during the online upgrade and so the server has both the old and new schema representations in memory to perform the comparison.
With Amster this process changes. The Amster deployment process requires that configuration from a previous version is exported to Amster export files, upgraded offline, and then imported into a clean installation of the new server. This means that any new attributes or services will be automatically present in the new server as part of its clean installation.
The FBC storage mechanism is only intended for use with Docker images in an automated cloud deployment. The base AM Docker image uses a base configuration which represents the default AM configuration. Like the other approaches this means attribute and service addition/deletion is handled automatically by the base configuration. The customer is expected to only maintain their custom configuration overlays which are to be layered ontop of the base configuration.