What has been removed in Mule 4 compared to Mule 3 regarding data transfer?

In Mule 4, session variables have been removed in favor of a more streamlined and efficient approach to data management. In Mule 3, session variables allowed data to be shared across flows within a single execution context. However, in Mule 4, data transfer and state management have been redesigned to improve performance and scalability.

Instead of session variables, Mule 4 emphasizes the use of the payload and attributes for transferring data between components. This design choice helps to simplify the overall architecture by reducing the complexity associated with managing state across different flows. By not relying on session variables, Mule 4 can focus more on event-driven programming paradigms, enabling better handling of distributed systems and asynchronous processing.

This change reflects a broader shift in the way MuleSoft encourages developers to manage data flows, promoting the use of lightweight approaches that are easier to maintain and scale.