F11 (03 §3.1): Delivery.PartitionKey is populated only for partitioned subscriptions, so changing the mode under existing deliveries would leave them inconsistent. New records and unchanged modes never reach the database.
F11 (03 §3.1): Delivery.PartitionKey is populated only for partitioned subscriptions, so changing the mode under existing deliveries would leave them inconsistent. New records and unchanged modes never reach the database.