Before making software, software developer make a document to prepare algorithm and databases , how many user can used this software, what is length of the organization, which tool is suit for this software and which one is not best, update is required , and when its updated, and Dynamic user requirements is basically run time requirement for user to do current tasks.
A number of technique are there to deal with dynamic user requirements. It depends on what kind of system do you have. For example, in case of ecosystems the approach is different. Need more specific question
Know the company's requirements for the coming years and develop a strong business plan strategy to create and design a dynamic system to deal with the required developments, while adding the possibility of the system to respond without the need for major changes.