# Next.js v16.3.1-canary.15

- Product: Next.js (https://whatsnew.fyi/product/next-js)
- Vendor: Vercel
- Date: 2026-08-12
- Version: v16.3.1-canary.15
- Original notes: https://github.com/vercel/next.js/releases/tag/v16.3.1-canary.15
- Permalink: https://whatsnew.fyi/product/next-js/releases/v16.3.1-canary.15
- 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'.

---

- **fixed** — Fix typo 'ouput' in parseIdsFromCliOutput
- **changed** — Add the mtime fallback back
- **changed** — Stop serializing hmr version state
- **fixed** — Fix HMR for dynamic imports evaluated from layouts
- **changed** — Add clusters to chunking heuristics
- **changed** — Allow running ncc before pnpm build
- **changed** — Invalidate deferred Webpack entry sources

###### Misc Changes

- test: fix 'ouput' typo in parseIdsFromCliOutput: #97266
- Add the mtime fallback back: #97268
- Allow issue participants to request reopening: #96947
- [turbopack] Document clusters for chunking: #97267
- Link to issues in the contribution guide and discourage trivial PRs: #97188
- Stop serializing hmr version state: #97146
- [turbopack] Add `clusters` to chunking heuristics: #95157
- [test] Redirect the deployment host in-process for proxy deploy tests: #97260
- [test] Unflake two `cache-components-dev-streaming` assertions: #97246
- [test] Unflake `use-cache-default-profile-expire-zero` tests: #97250
- [turbopack] Fix HMR for dynamic imports evaluated from layouts: #97213
- [ci] Use OIDC tokens to read private preview builds: #96919
- Allow running `ncc` before `pnpm build`: #97234
- Invalidate deferred Webpack entry sources: #97205

###### Credits 

Huge thanks to @syedsohailhussain1, @lukesandberg, @marcoshernanz, @sampoder, @unstubbable, @eps1lon, and @gnoff for helping!