Backward Compatibility Audit

Compare these API versions for breaking changes:

Old version:
{{old_version}}

New version:
{{new_version}}

Context:
- Consumers: {{consumer_count}}
- Criticality: {{criticality}}
- Migration window: {{migration_window}}

For each breaking change:
1. Impact assessment (affected consumer %)
2. Deprecation strategy (dual-version, date-based, etc.)
3. Client migration guide
4. Monitoring plan (detection of old-version calls)
5. Rollback plan