# Preact 11.0.0-rc.0

- Product: Preact (https://whatsnew.fyi/product/preact)
- Vendor: Preact
- Date: 2026-08-10
- Version: 11.0.0-rc.0
- Original notes: https://github.com/preactjs/preact/releases/tag/11.0.0-rc.0
- Permalink: https://whatsnew.fyi/product/preact/releases/11.0.0-rc.0
- 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'.

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- **added** — Implement use hook in compat
- **added** — Implement getServerSnapshot for useSyncExternalStore
- **added** — Support createPortal in core
- **added** — Add useEffectEvent hook to compat
- **changed** — Leverage moveBefore rather than insertBefore when available
- **fixed** — Avoid mutating user-provided style objects when appending px
- **fixed** — Fix reusing template element content
- **fixed** — Fix dirty child strict equality bailout
- **fixed** — Add the constructor in when cloning VNodes
- **fixed** — Defer passive effect cleanup on unmount
- **changed** — Compute minimal child moves with a longest increasing subsequence
- **changed** — Batch updates in flushSync
- **changed** — Avoid traversing retained subtrees
- **changed** — Reduce core bundle size in v11
- **changed** — Reduce bundle size before release candidates go live
- **changed** — Hoist _children into a local in constructNewChildrenArray
- **changed** — Reduce Preact core compressed size
- **changed** — Bump reported React version to 19.0.0
- **fixed** — Avoid Trusted Types violation when dangerouslySetInnerHTML is used
- **changed** — Introduce a modern build setup

##### Features

- implement `use` in compat (#5186, thanks @JoviDeCroock)
- Implement getServerSnapshot for useSyncExternalStore (#4979, thanks @ssssota)
- Support createPortal in core (#5168, thanks @JoviDeCroock)
- Add useEffectEvent hook to compat (#5141, thanks @Mesoptier)

##### Correctness

- Leverage `moveBefore` rather than `insertBefore` when available (#5161, thanks @JoviDeCroock)
- Avoid mutating user-provided style objects when appending px (#5117, thanks @JSap0914)
- Fix reusing template element content (#5192, thanks @JoviDeCroock)
- Fix dirty child strict equality bailout (#5193, thanks @JoviDeCroock)
- Add the constructor in when cloning VNodes (#5195, thanks @JoviDeCroock)
- Defer passive effect cleanup on unmount (#5196, thanks @JoviDeCroock)

##### Performance

- Compute minimal child moves with a longest increasing subsequence (#5174, thanks @JoviDeCroock)
- Batch updates in flushSync (#5175, thanks @JoviDeCroock)
- Avoid traversing retained subtrees (#5183, thanks @JoviDeCroock)
- Reduce core bundle size in v11 (#5167, thanks @JoviDeCroock)
- Reduce bundle size before release candidates go live (#5197, thanks @JoviDeCroock)
- Hoist `_children` into a local in `constructNewChildrenArray` (#5198, thanks @JoviDeCroock)
- Reduce Preact core compressed size (#5199, thanks @JoviDeCroock)

##### Maintenance

- Bump reported React version to 19.0.0 (#5171, thanks @JoviDeCroock)
- Remove debug re-throw (#5190, thanks @JoviDeCroock)
- Commit pending hook state in `options._render` (#5187, thanks @JoviDeCroock)
- Remove straggler forwarded (#5178, thanks @JoviDeCroock)
- Derive document from parentDom instead of threading it (#5180, thanks @JoviDeCroock)
- Remove redundant portal children guard (#5179, thanks @JoviDeCroock)
- Restore `_bits` mangle for Preact ISO (#5200, thanks @JoviDeCroock)
- Update contribution build commands (#5166, thanks @Minsecrus)
- Remove unused dependencies (#5160, thanks @JoviDeCroock)
- Avoid Trusted Types violation when dangerouslySetInnerHTML is re… (#4935, thanks @lukewarlow)
- Introduce a modern build setup (#5159, thanks @JoviDeCroock)