v15.4.2-canary.27

Core Changes

• Turbopack: Compact only at the end for short sessions: #82224
• feat: add fallback root params support for prefetch segment data routes: #82282
• feat: add route context to prerender error messages: #82283

Misc Changes

• docs: to indicate that redirect can be used in both server and client…: #82092
• Turbopack: improve compression dictionary generation: #80061
• test: reduce artificial timeouts in runtime prefetch tests: #82276
• Turbopack: fix glob with empty alternative branch: #82275
• [turbopack] Optimize ESM exports: #82214
• [turbopack] Fix a snapshot test: #82281
• [turbopack] Avoid calling find_server_entries in the whole_app_module_graph case: #81943
• docs: Add Tolgee to app router localization resources: #81366
• Update Rspack development test manifest: #82268
• Update Rspack production test manifest: #82267

Credits

Huge thanks to @sokra, @candymask0712, @lubieowoce, @mischnic, @lukesandberg, @wyattjoh, @stepan662, and @vercel-release-bot for helping!

v15.4.2-canary.26

Core Changes

• Mark bun builtin modules as external (fixes #75220): #77616

Misc Changes

• [turbopack] Adopt rcstr! more consistently: #80552
• Turbopack: use mimalloc v3: #82221
• Turbopack: no need to avoid allocations anymore: #82222
• Turbopack: ensure max merge segments is respected accros families: #82223

Credits

Huge thanks to @lukesandberg, @sokra, and @Jarred-Sumner for helping!

v15.4.2-canary.25

Core Changes

• Upgrade React from 9784cb37-20250730 to c260b38d-20250731: #82247
• [Cache Components] Runtime prefetching: #81088
• Parse dynamic params on the client: #82185

Misc Changes

• fix: turbopack loader ipc field mapping: #82112
• Turbopack: fix dev test manifest: #82241
• fix(Turbopack): Fix duplicated layout rendering in edge cases: #81948

Credits

Huge thanks to @dlehmhus, @mischnic, @Cy-Tek, @lubieowoce, and @acdlite for helping!

v15.4.2-canary.24

Core Changes

• Fix: Don't bail out of prefetch if head is missing: #82216

Misc Changes

• Turbopack: implement shutdown for backing storage correct: #82220
• Update Rspack development test manifest: #82227

Credits

Huge thanks to @acdlite, @sokra, and @vercel-release-bot for helping!

v15.4.2-canary.23

Core Changes

• Revert "Initial MCP implementation (#81770)": #82217
• Revert "Upgrade @vercel og (#82201)": #82219

Misc Changes

• Update Rspack production test manifest: #82108
• Update Rspack development test manifest: #82192

Credits

Huge thanks to @vercel-release-bot, @sokra, and @huozhi for helping!

v15.4.2-canary.22

Core Changes

• allow root params access in private caches: #82125
• [devtool] bump base-ui to 1.0.0-beta.2: #82206
• Upgrade @vercel og: #82201
• Upgrade React from 9be531cd-20250729 to 9784cb37-20250730: #82207
• Fix: the unexpected clearing of symbolic link directories: #82191
• [next-dev] Set TURBOPACK env before loading config: #82162
• fix: display multiple lockfile warn if neither outputFileTracingRoot or turbopack.root option is provided: #82164

Misc Changes

• Turbopack: Use Path/PathBuf for all of the invalidation logic: #82132
• Turbopack: Use a BTreeMap in InvalidatorMap to avoid many O(n) traversals when finding child paths: #82133
• Turbopack: Watch the root and every parent directory in non-recursive mode: #82129
• Turbopack: Remove unused ignored_subpaths feature from DiskWatcher: #82210
• Grammar fix on forms.mdx: #82209

Credits

Huge thanks to @lubieowoce, @huozhi, @bgw, @startracex, @chadfennell, and @devjiwonchoi for helping!

v15.4.2-canary.21

Core Changes

• Fix RSC hash validation for middleware external rewrites: #82176
• @next/codemod: update docs url in README: #82135
• @next/codemod: Add experimental.turbo to turbopack codemod for Next.js configs: #82134
• refactor: lowercase app router header values: #82169
• Strip internals from NextRequest types: #82172

Misc Changes

• docs: update cacheTag.mdx: #82051
• Turbopack: Make the "non-recursive" logic for the fs watcher a runtime flag instead of a build-time one: #82031
• Turbopack: Add a flag to the fs watch fuzzer to print missing but expected invalidations: #82131
• docs: fix typo in docs: #82186
• docs: Add more links to app docs root: #82126
• docs: App Router's React version: #82180

Credits

Huge thanks to @gaojude, @wbinnssmith, @m1abdullahh, @bgw, @Sayakie, @icyJoseph, @lubieowoce, and @eps1lon for helping!

v14.2.31

Note

This release is backporting bug fixes. It does not include all pending features/changes on canary.

Core Changes

• fix(next/image): improve and simplify detect-content-type (#82179)
• fix(next/image): fix image-optimizer.ts headers (#82178)

Credits

Huge thanks to @styfle and @ztanner for helping!

v15.4.5

Note

This release is backporting bug fixes. It does not include all pending features/changes on canary.

Core Changes

• Fix API stripping JSON incorrectly (#82062)
• Fix i18n fallback: false collision (#82158)
• Revert "Fix tracing of server actions imported by client components (#82167)
• Ensure setAssetPrefix updates config instance (#82165)
• Turbopack: update mimalloc (#82166)
• fix(next/image): fix image-optimizer.ts headers (#82175)
• fix(next/image): improve and simplify detect-content-type (#82174)

Credits

Huge thanks to @ijjk, @sokra, and @styfle for helping!

v15.4.2-canary.20

Core Changes

• Extract getDynamicParam to a shared module: #82137
• Fix i18n fallback: false collision: #82136
• [segment explorer] normalize path when running inside monorepo: #82146
• [segment explorer] windows compatibility: #82147
• Upgrade React from eaee5308-20250728 to 9be531cd-20250729: #82159
• Ensure setAssetPrefix updates config instance: #82160
• Revert "Fix tracing of server actions imported by client components (#78968): #82161
• Remove useMDXComponents argument: #80871

Misc Changes

• Update Rspack production test manifest: #82139
• Turbopack: Fix accidental doctest in globset module license: #82127
• [turbopack] tweak the ui of the module-cost benchmark: #81817
• [test] revert config change in hello-world test: #82173
• docs: cookies.set encode option is not supported: #82154
• docs: change Dashboard component to async for session verification: #81880
• Update create-release-branch to disable test-new-tests: #82182

Credits

Huge thanks to @acdlite, @ijjk, @huozhi, @vercel-release-bot, @bgw, @lukesandberg, @icyJoseph, @remcohaszing, and @wesjune for helping!