Which of the following is not a main function of middleware?

Middleware serves as a bridge allowing different systems, applications, and services to communicate and manage data effectively. The main functions typically associated with middleware include ensuring data integrity, managing communication protocols, and integrating different applications.

Facilitating user interface design is not one of the primary functions of middleware. Instead, middleware focuses on backend communication and management while user interfaces are usually handled by front-end application frameworks or libraries. Therefore, while an application might include both middleware and user interface components, middleware itself does not specifically handle or focus on UI design. Its role is centered on supporting application integration and communication rather than directly influencing how a user interacts with the software visually.