BDM Architecture Principle 10: Principle: Minimize changes to legacy. Statement: Minimize changes and write-back to legacy. Rationale: Co-existence model inherently leads to significant complexity. BDM needs to design deployment strategy, transition architecture, services, processes and integration between new solutions and legacy to control complexity and risk. One of the approaches to control complexity is to minimize changes to legacy. Implications: Architecture objectives and planning assumptions (to be validated through prototyping): • There will be one system of record for each transaction. • Transactions will be process either in the new or legacy system, not in both. • Data will be accessed in the other system as needed. • Certain amount of data will be migrated to the new system.