What is a limitation of outbound messages when sending Opportunities to an external ERP system that only supports SOAP messages?

The limitation of outbound messages when sending Opportunities to an external ERP system that only supports SOAP messages lies in the inability to support multiple objects. Outbound messages in Salesforce are designed to send notifications when a specific record is created or updated, and they are restricted to a single object type. This means that if there is a requirement to send data related to multiple objects at once, such as both Opportunities and related Products, outbound messaging would not be capable of handling that in a single transaction.

In scenarios where an integrated system requires comprehensive data from various related Salesforce objects, relying solely on outbound messages becomes impractical. This limitation necessitates the use of alternative integration approaches, such as REST APIs or custom Apex solutions, which can handle complex data structures and multiple object types in a single request.

Understanding this limitation is crucial for architects and developers when designing integrations between Salesforce and external systems, especially when the external system only supports specific protocols or formats such as SOAP.