Geodatabase replication is designed to synchronize data edits (inserts, updates, and deletes) but not schema changes. When a field is added to the parent replica's source data, the existing replication agreement is unaware of this structural change. The synchronization process continues to operate based on the original schema defined when the replica was created. Therefore, the new field and its values are not sent to the child. The only officially supported method to apply schema changes to replicated data is to remove the existing replica relationship, apply the schema changes to the source data, and then create a new replica. This ensures the new replica is based on the updated schema.

A. Enable Replica Tracking is a prerequisite for creating replicas, not a tool to update an existing replication schema. You cannot synchronize after unregistering a replica.

B. Feature Compare is a data analysis tool used to identify differences between datasets; it does not manage or repair the replication process or schema.

1. Esri ArcGIS Pro Documentation, "Geodatabase replication fundamentals": Under the section "Replication and geodatabase compatibility," the documentation states, "Once data is replicated, you should not make schema changes to the data in the parent or child geodatabase. If you need to make schema changes, you must first unregister the replica." This directly supports the need to unregister the replica before proceeding.

2. Esri ArcGIS Pro Documentation, "Create Replica (Data Management)": The usage notes for this geoprocessing tool imply that the schema is fixed at the time of creation. The tool's purpose is to establish a replica based on the current state and schema of the source data. This supports the need to recreate the replica to capture the new schema.

3. Esri ArcGIS Enterprise Documentation, "Prepare data for replication": This guide details the steps needed before creating a replica, including schema finalization. It states, "Before replicating, it is important to have the geodatabase design finalized. Schema changes made after a replica is created are not sent during synchronization." This confirms that schema changes are not propagated and necessitates the unregister/recreate workflow.