# Deprecations and migrations Use this file when you must change saved markup or attribute shapes without breaking existing content. ## `deprecated` basics Block deprecations are handled in JS block registration. - Add older implementations to `deprecated` (newest → oldest). - Each deprecated entry can include: - `attributes` - `supports` - `save` - `migrate` Upstream reference: - https://developer.wordpress.org/block-editor/reference-guides/block-api/block-deprecation/ ## Practical guardrails - Keep fixtures: store example content for each deprecated version. - When in doubt, add a migration path rather than silently changing selectors.