The nice thing about Agile is it simplifies many things. The concept of an MRD is still valid but it functions as more of a directional document that guides a series of sprints. It’s purpose it to spell out the main goals and objectives of your target customers, why they’re important and how your solutions will help them achieve those goals. Make your MRD a 1-pager that contains the following information. Target market segments and the target-customer departments the series of sprints will target. For each target-customer department list their business goals and the key obstacles your series of sprints will address. That’s it! Your subsequent user stories or epics are the supporting information that spell out how those obstacles will be removed and help the target-customer department meet it’s goals.