From 20-year-old warehouse SCDs to a modern temporal backbone you can trust. This article lays out a practical, regulator-aware playbook for migrating legacy EDW SCD dimensions to a modern SCD2 Bronze layer in a medallion/lakehouse architecture. It covers what you are really migrating (semantics, not just tables), how to treat the EDW as a source system, how to build canonical SCD2 Bronze, how to run both platforms in parallel, and how to prove to auditors and regulators that nothing has been lost or corrupted in the process.