Migration

JSON is the canonical document format. Persist and exchange editor.getJSON() / Snapshot.doc (JSONContent: ProseMirror node JSON).

Quill Delta is not supported. There is no Delta import, no ops array, and no converter in this SDK. A legacy Delta document must be rewritten to ProseMirror JSON (nodes, marks, attrs) before Editor.create({ content }) or setContent.

HTML is not a storage format. Use it for paste, print, and getHTML() only. Comment marks are omitted from HTML; round-tripping HTML will drop threads.

Collaborative history is a step log against docsSchema(), not a CRDT. OT runs through prosemirror-collab. There is no Yjs document and no suggestion-mode layer to migrate.

Checklist:

• Store JSONContent, not Delta, not HTML.
• Comment bodies live beside the doc (CommentThreadWire[] on Snapshot.comments), not as Delta attributes.
• Re-home any custom Quill blot onto an Extension (nodes / marks / commands / keymap).
• Authority and clients must share docsSchema() (or the same schemaFromExtensions list).