Legacy System (glossary)
A comprehensive, integrated plan that identifies the acquisition approach and describes the business, technical, and support strategies that management will follow to manage program risks and meet program objectives. The Acquisition Strategy should define the relationship between the acquisition phases and work efforts, and key program events such as decision points, reviews, contract awards, test activities, production lot/delivery quantities, and operational deployment objectives. (DAU February 19, 2010)
DAU. February 19, 2010. Defense Acquisition Guidebook (DAG). Ft. Belvoir, VA, USA: Defense Acquisition University (DAU)/U.S. Department of Defense (DoD).
Discussion as to why this is the "consensus" definition for the SEBoK.