# XState 6.0.0-alpha.40

- Product: XState (https://whatsnew.fyi/product/xstate)
- Vendor: Stately
- Date: 2026-08-17
- Version: 6.0.0-alpha.40
- Original notes: https://github.com/statelyai/xstate/releases/tag/xstate%406.0.0-alpha.40
- Permalink: https://whatsnew.fyi/product/xstate/releases/6.0.0-alpha.40
- Labels: Pre-release

What's New is an index, not a publisher: every entry below links to the vendor's own release notes, which are the authoritative source. Entries are labelled where they are hand-curated sample data, pre-releases, or drawn from a secondary source such as a developer blog.

Reuse: the summaries, labels and curation here are © What's New. Quote freely with attribution and a link back; wholesale republication of the corpus is not permitted — terms: https://whatsnew.fyi/terms. The vendors' own release notes remain their publishers'.

---

- **changed** — Represent historical machine versions with Standard Schema snapshot and event descriptors instead of retaining their executable machines, with versioned machines exposing the same snapshotSchema and eventSchema interface
- **changed** — Machine-backed snapshot schemas now default omitted history and timer records during migration
- **fixed** — actor.getPersistedSnapshot() is now typed to the actor's logic so persist/restore round-trips through createActor(logic, { snapshot }) no longer require a cast

###### Minor Changes

- 107d0c2: Represent historical machine versions with Standard Schema snapshot and event
  descriptors instead of retaining their executable machines. Versioned machines
  expose the same `snapshotSchema` and `eventSchema` interface. Machine-backed
  snapshot schemas default omitted history and timer records during migration.
  
  ```ts
  const versions = machineVersions([
    {
      id: 'checkout',
      version: '1',
      snapshotSchema: checkoutV1Snapshot,
      eventSchema: checkoutV1Event
    },
    checkoutV2
  ]);
  
  const snapshot = await versions.migrateSnapshot(persisted, {
    to: '2',
    migrations: {
      '1': (snapshot) => ({
        ...snapshot,
        context: { total: snapshot.context.count }
      })
    }
  });
  ```

###### Patch Changes

- 2e77ff6: `actor.getPersistedSnapshot()` is now typed to the actor’s logic, so persist/restore round-trips through `createActor(logic, { snapshot })` no longer require a cast. Restoring a snapshot into a machine with a different `id` is a type error, while snapshots from other versions of the same machine remain assignable (for runtime migration via `migrate`).
  
  ```ts
  const actor = createActor(machine).start();
  const snapshot = actor.getPersistedSnapshot();
  
  // No cast needed:
  const restored = createActor(machine, { snapshot }).start();
  ```