Write a migration guide

Help me write a migration guide.
Inputs: from version; to version; changes.

1. Identify who must migrate.
2. sequence checks, backup, transformation and validation.
3. explain coexistence, irreversible steps and failure handling.

Deliver: Who needs this, Before you start, Breaking changes, Deprecations, Verify the upgrade.
Clarify critical gaps, separate facts from assumptions, and do not invent data, citations or completed actions.

My material: [fill in here]

事前準備

Provide from version; to version; changes.