v1.13.0

**We recommend all users upgrade.** v1.13.0 is our **biggest content-processing upgrade yet**: it rebuilds extraction on top of **Content Core 2.0** (a major architecture release), adds opt-in **Docling** (OCR + layout-aware parsing) and **Crawl4AI** (JavaScript rendering) engines, brings **EPUB and Reddit** support, moves PDF extraction to MIT-licensed pdfplumber, fixes audio extraction, and keeps the default image lean by making the heavy runtimes opt-in. Plus a batch of podcast correctness fixes. Validated with the release confidence process: full backend/frontend suites, the fresh-install + upgrade image gate, and manual verification of the opt-in runtimes, real podcast/TTS and PDF extraction on the pushed image.

## ✨ A major content-processing upgrade (Content Core 2.0)

Extraction now runs on **content-core 2.x** — a ground-up refactor of the extraction stack. What it means for you:

- **Docling document engine (opt-in)** — real **OCR for scanned PDFs and images** plus layout-aware parsing. Toggle OCR in Settings → Content Processing (on by default; turn it off to speed up text-native docs). (#1104)
- **Crawl4AI URL engine (opt-in)** — renders **JavaScript-heavy pages** locally with no API key, or offloads to a Crawl4AI server (`CRAWL4AI_API_URL`). Selectable alongside Firecrawl, Jina and Simple. And **your persisted engine choice now actually takes effect** — the source-processing graph reads the saved Content Settings and passes them to content-core (it previously always ran `auto` and silently ignored the selection). (#432)
- **New formats** — **EPUB** books are now supported, and **Reddit** links extract the post *and* its comments automatically.
- **Better PDF & audio** — PDF extraction moves to **MIT-licensed pdfplumber** (replacing AGPL PyMuPDF), and audio moves to direct ffmpeg calls — faster, and it **fixes extraction from MP3 files carrying chapter metadata**. (#1103)
- **Faster, clearer failures** — unsupported uploads are rejected instantly at ingestion with a `415` naming the detected type, instead of a background job retrying for ~an hour. (#975)

## 🪶 Lean by default, powerful on demand

- **The heavy runtimes are opt-in.** Docling and local Crawl4AI are no longer bundled into every image — they install automatically on first container startup when enabled. Set `OPEN_NOTEBOOK_ENABLE_DOCLING=true` and/or `OPEN_NOTEBOOK_ENABLE_CRAWL4AI=true`; downloads are cached on the `/app/data` volume (only the first boot is slow), and a failed install degrades gracefully (the app still starts, the engine is reported unavailable) with loud logs. A new `GET /api/capabilities` probe reports what's actually installed, and Settings → Content Processing disables the Docling/Crawl4AI engines and the OCR toggle (with an env-var hint) until their runtime is available — so the UI never advertises an engine that isn't there. A remote Crawl4AI server needs no local install. Recorded as ADR-007. (#1122)
- Source extraction now **logs the effective engine** (`url_engine` / `document_engine` / `docling_ocr`) at INFO right before it runs, so you can confirm which engine actually processed a source instead of guessing. (#1125)

## 🐛 Notable fixes

- **Podcast correctness**: renaming a speaker profile no longer breaks the episode profiles using it (references are stored by record ID, not name); episode audio paths are stored **relative** to the podcasts folder so previously generated episodes survive a `DATA_FOLDER` relocation; episode cards resolve and show the real outline/transcript/speaker model instead of "— / —"; and podcast generation now honors an explicitly supplied `speaker_profile` all the way into the generation command. (#630, #1030, #1114, #1058)
- Clicking a chat/Ask citation that points at a **deleted source, insight or note** now shows a friendly "this content no longer exists" state in all three dialogs. (#455)
- Source insights get `created`/`updated` timestamps and the API returns `null` (not the literal string `"None"`) for legacy insights. (#1045)
- Optional model defaults (transformation, tools, large context, TTS, STT) can now be **cleared** via `PUT /api/models/defaults` (chat and embedding still can't be null). (#1091)
- **Creating a transformation from the empty state works again** — after deleting every transformation, the "New Transformation" button did nothing. (#999)
- The source detail view now fetches through the shared React Query hook (consistent caching and 404 handling), and the settings UI reads the provider list from `GET /api/providers` so new providers need zero frontend edits. (#1106, #1082)
- `uv sync` alone now provides the full dev toolchain (mypy included). (#1101)

## ⚠️ Behavior changes for self-hosters

1. **Docling and local Crawl4AI are now opt-in.** If you relied on Docling parsing/OCR or local Crawl4AI rendering, set `OPEN_NOTEBOOK_ENABLE_DOCLING=true` and/or `OPEN_NOTEBOOK_ENABLE_CRAWL4AI=true` — the first container boot then installs them (cached afterwards). The default image no longer ships Chromium or the multi-GB ML stack. A remote Crawl4AI server (`CRAWL4AI_API_URL`) needs no local install.
2. **Persisted engine selections now take effect.** If you had a document/URL engine selected in Settings → Content Processing, it was previously ignored (everything ran `auto`); it now actually applies. Re-check your selection after upgrading — and remember to click **Save** for it to persist.
3. **Frontend bind override changed.** Docker images force the Next.js frontend to bind `0.0.0.0`; the `HOSTNAME` variable is no longer honored as a bind override — use the new `FRONTEND_BIND_HOST` variable instead. (#994)
4. **Podcast profile migrations (19–22) apply automatically on startup.** Profiles whose legacy model mapping never converged (e.g. a provider credential was never configured) may need you to re-pick the models/speaker in the profile form once. Podcast episodes stored under non-standard absolute paths are treated as legacy-invalid — regenerate to restore playback.
5. **`docker-compose.yml` SurrealDB command** now uses the YAML list (exec) form, so `SURREAL_USER` / `SURREAL_PASSWORD` values containing spaces are passed correctly. (#1093)

## 🙏 Thanks

- **@pelazas** — fixed the transformation editor being unreachable from the empty state (#999).
- **@lfnovo** — the opt-in runtime system (#1122), the Crawl4AI URL engine and persisted-engine wiring (#432), the OCR toggle (#1104), the content-core 2.x upgrade (#1103), the podcast correctness batch (#630, #1030, #1114, #1058), the 415 ingestion guard (#975), and the rest of the release.

And a collective thank-you to everyone who **filed issues and reported bugs** that shaped this release — the deleted-citation UX, the engine-selection gap, the podcast speaker/rename cases, and more.

Full details in the [CHANGELOG](https://github.com/lfnovo/open-notebook/blob/main/CHANGELOG.md).