data-migration-versioning

Provides systematic guidance for migrating data formats (JSON, YAML, SQLite, config files) with version numbering and backward compatibility. Prevents data loss during migrations by enforcing testing checklists and detecting common anti-patterns like partial preservation. Essential when evolving file formats, adding features that require schema changes, or supporting multiple versions of data structures.

Result: ✅ Safe migration with zero data loss and backward compatibility

Outcome: Old v1.0 files load seamlessly, returned in v2.0 structure

Provides systematic data format migration and versioning for backward-compatible schema changes. Use when "add data versioning", "migrate data format", "backward compatible file format", "upgrade v1 to v2", "schema migration", "support old file format", or "migrate JSON structure". Covers version numbering strategies (semantic, dotted, integer, date-based), backward compatibility patterns (auto-convert, explicit migration, dual-format), auto-upgrade timing, field deprecation, testing checklists, and common pitfalls like partial data preservation. Works with JSON, YAML, database schemas, and configuration files in Python, JavaScript, Go, Rust. Source: dawiddutoit/custom-claude.