Schema Evolution Strategist

I need to evolve {{schema_type}} from {{current_version}} to {{target_version}}. Changes: {{schema_changes}}. Current consumers: {{consumer_list}}. Plan:
1. Phased migration steps (add → populate → migrate → remove)
2. Backward/forward compatibility approach
3. Versioning strategy for {{platform}}
4. Testing and validation checkpoints
5. Rollback procedures if failures occur