> ## Documentation Index > Fetch the complete documentation index at: https://docs.kordless.ai/llms.txt > Use this file to discover all available pages before exploring further. # Versions and replay > How Book versions work, why they are immutable, and why Quotes can be replayed exactly. Every published Book is an immutable version. Quotes are pinned to the exact version that produced them. This means any Quote can be replayed — the same request against the same version produces the same result. ## Immutable versions When you publish a Book, Kordless creates an immutable version. The version: * Cannot be edited, patched, or selectively modified * Has a version number (1, 2, 3, …) * Contains the exact rules, factors, tables, and policies that were verified * Is addressable by its version number To change a Live Book, you propose a change, preview its impact, and publish a new version. The previous version remains intact and addressable. See [Update a Live Book](/product/book/update-live-book) for the change sequence. ## Version numbering * The first published version is **version 1**. * Each subsequent publication increments the version number. * The Preview and publish page shows the next version number before you publish. * The Book overview shows the current Live version number (for example, `v3`). ## What changes when you publish a new version When you publish a new version: * **New quotes** use the new version. * **Existing offers** (Quotes already sent or in progress) remain pinned to the version that produced them. * **Regression cases** replay against the new version automatically. * **The published Book page** updates to show the new version. The Preview and publish page tells you how many outstanding offers remain pinned to the current version before you publish. ## Why Quotes can be replayed Every Quote records: * The exact **Book version** that produced it * The **structured input** — the normalized requirements * The **derivation** — how each line item was calculated * The **conditions** — availability, policy, and validity * The **review or override record** — any owner action taken on the result Because the Book version is immutable and the inputs are recorded, the same request against the same version always produces the same result. This is what makes a Quote trustworthy: it is not a snapshot of a moment — it is a deterministic computation against a fixed artifact. ## Scenario replay When you publish a new version, Kordless replays all confirmed calibration and historical cases against the candidate version. The Preview and publish page shows: * The total number of scenarios replayed * Only changed outcomes — scenarios where the result differs between the current and candidate version If no outcomes changed, the section reads: "No tested outcome changes. The cases still replayed and passed against the candidate artifact." ## The regression suite Confirmed calibration cases become part of the permanent regression suite. Every case in the suite replays each time the Book is compiled or published. A case marked **Needs attention** means the current draft produces a different result from what you confirmed — a signal that something changed and needs review. ## Published Book pages Each published version has a public slug. After publishing, you can open the published Book page to see the version that is Live. The published page shows the rules, services, and coverage of that version. ## Version lifecycle ```text theme={null} Draft workspace → Verified draft → Published as immutable version N → Live for new quotes → A change is proposed → Draft workspace (alongside Live) → Verified → Published as immutable version N+1 → Version N remains addressable → Existing offers remain pinned to version N ``` ## Related Review consequences and publish an immutable Book version. Propose, preview, and authorize a change to a Live Book.