[Launch options](https://cdpfleet.com/docs/options)

# `version`

Pin an older major version.

**Use it for:** Reproducing a bug on an older browser, keeping a scraper on a known-good build while you test the new one, or matching a customer's browser.

**Browsers:** [Google Chrome](https://cdpfleet.com/docs/browsers/chrome#opt-version), [Camoufox](https://cdpfleet.com/docs/browsers/camoufox#opt-version).

## Details

-   **Type:** `string`
-   **Default:** none (latest stable)
-   **Example:** `{"version":"152"}`

Request a retained previous major, e.g. `"152"`. The majors available right now are listed on the browser's page. A major no server in the fleet has returns `400 {"error": "invalid_version"}` with the majors you can pin in `message`, rather than silently running a different version; one that exists but has no free server right now returns `503 version_unavailable`.

Previous majors rotate out automatically: Chrome keeps its two most recent previous majors and drops the oldest within about a day of a new stable release; Camoufox keeps recent majors plus long-term ones. Read the live list rather than hard-coding a number. Send either `version` or a pre-release `channel`, not both: together they return `400` (`channel: "stable"` with a `version` is fine).

## Used in

-   [Case 3: Stable, beta, dev and an older major: four Chromes side by side](https://cdpfleet.com/docs/cases/chrome-versions)
-   [Pin an older Chrome major (156)](https://cdpfleet.com/docs/examples#pinned-version)
-   [Camoufox: pinned version, macOS persona, no images](https://cdpfleet.com/docs/examples#camoufox-lean-persona)

All options: [launch options](https://cdpfleet.com/docs/options).

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Source: https://cdpfleet.com/docs/options/version · Markdown: https://cdpfleet.com/docs/options/version.md · All docs for AI tools: https://cdpfleet.com/llms.txt