Frontend Frameworks

Next.js re-enables AVIF optimization; EAS CLI adds SSH sessions

Next.js restored AVIF image optimization across stable and LTS lines after a regression, while EAS CLI shipped SSH access to workflow workers and SDK-version prompts for new projects.

• —Next.js re-enables AVIF image optimization in both v16.3.4 and v15.5.25, fixing the regression from previous releases, plus backports a testmode fetch infinite-recursion fix.
• —EAS CLI adds `eas workflow:ssh` to shell into workflow job workers and a `--ssh` flag for workflow runs, letting you debug builds interactively.
• —EAS CLI now prompts for the Expo SDK version in `eas new` (with a `--sdk-version` flag) and pulls templates from npm instead of GitHub.
• —Next.js canary improves Turbopack HMR recovery after dropped connections, passes original searchParams for private-cache pages, and simplifies "use cache" error messages.

Codemods and EAS CLI ship upgrade-friendly changes

Next.js improved its upgrade codemods for .mjs files and non-interactive environments, while EAS CLI v23 introduced a breaking session-type rename and faster iOS builds via CocoaPods caching.

• —Next.js codemods now transform .mjs files and respect non-interactive mode in upgrade prompts.
• —EAS CLI renamed the simulator preview session type to `web-preview-only` and caches CocoaPods dependencies between iOS builds.

Next.js and Svelte refine routing and context APIs

Svelte 5.57 expands server exports and context utilities while Next.js's canary fixes encoded dynamic params and intercepted route params after proxy rewrites.

• —Next.js fixes optimistic routing for encoded dynamic params and intercepted route params after proxy rewrites in its latest canary, plus adds more granular use-cache keys.
• —Svelte 5.57 exports RenderOutput, SyncRenderOutput, Csp, and Sha256Source from svelte/server, and adds a has function to createContext.
• —Svelte also supports defaultValue on select elements and adds getOrInsert/getOrInsertComputed to SvelteMap.

Next.js tightens image handling, EAS simulator grows idle limits

Next.js canary rejects non-2xx image responses and replaces render bailout errors, while EAS CLI adds idle timeout and resource class flags to its simulator.

• —Next.js now rejects non-2xx internal image responses and re-enables AVIF optimization.
• —EAS CLI adds opt-in idle timeout and experimental resource-class flags to eas simulator.

Next.js patches critical RCEs, updates canary

Next.js released security patches for two critical unauthenticated RCE vulnerabilities across stable and canary channels, alongside canary improvements to Turbopack and WASM support.

Next.js refines partial prefetching, ships HMR and routing fixes

Next.js's canary adds unstable_prefetch() and instant validation for partial navigation, while a stable backport fixes catch-all pages hijacking unrelated slugs, plus Turbopack now isolates HMR listeners across microfrontends.

• —Next.js's Partial Prefetching gains instant validation for unstable_navigation() calls and a new unstable_prefetch() API to skip the preflight check.
• —The stable v16.3.2 backport stops catch-all index pages from being served for every other slug, fixing navigation and SSR edge cases.
• —Turbopack isolates HMR listeners per microfrontend and deduplicates Pages Router chunks to cut memory use and reload churn.
• —Next.js preserves trailing slashes during MPA fallback exports and validates app-entry exports scope to app-internal files only.

EAS Observe goes GA while SvelteKit preps split-serverless route adapters

Expo's EAS Observe observability platform graduated to general availability with new billing and retention terms, while SvelteKit's core and serverless adapters added early support for `applyReroute` in split deployments, and Next.js gained an unstable Partial Prerendering navigation API.

• —Expo's EAS Observe reached GA with 90-day retention on all plans; free-tier events start at 100K per month, with overage billed at $5 per million.
• —SvelteKit added an `applyReroute` adapter helper for split serverless deployments, applied across Vercel and Netlify adapters, plus earlier invalidation-result discarding on navigation.
• —Next.js introduced the unstable `unstable_navigation` API for Partial Prerendering and upgraded its vendored React build.
• —EAS CLI added Appium simulator session support and a `--device` flag, alongside GCS upload checksum validation and SDK-version repack resolution.
• —Svelte fixed CSS escape-sequence preservation in selectors and improved parsing of `:nth-child(... of ...)` expressions.

Next.js canaries sharpen Turbopack and dev previews

Next.js canary builds added Turbopack regex range support and more accurate dev-time prerender previews, while SvelteKit fixed an eager module-read edge case in a patch release.

• —Next.js Turbopack now handles character-class regex ranges and treats prerenders as render candidates, with a fix that stops stale pages from restoring during dev.
• —SvelteKit avoids eagerly reading $app/state dependencies during module initialization, preventing startup issues in patch 2.70.3.

Next.js persistence GC groundwork, Expo Orbit fixes signed-URL installs

Next.js's canary lays tombstone and delete plumbing for turbo-persistence garbage collection, while Expo Orbit patches a crash when installing builds from long signed URLs and several smaller correctness fixes.

• —Next.js canary adds key-value tombstones and delete/tombstone plumbing to turbo-persistence, preparing for garbage collection of cached builds.
• —Expo Orbit no longer crashes with ENAMETOOLONG when installing builds delivered via long signed URLs, including Android .apk installs, and fixes a file-handle leak and a large-size formatting error.

EAS CLI breaks JSON output; Next.js patches image cache

EAS CLI v22.0.0 renames fields in --json build output and adds source map uploads, while Next.js canary fixes an image disk-cache rejection and stale Turbopack route manifests.

• —EAS CLI v22.0.0 renames --json build fields (project, channel, runtimeVersion become app, updateChannel, runtime) and now uploads JavaScript source maps with builds.
• —Next.js canary rejects empty images on disk cache read/write and removes stale Turbopack manifests for deleted routes.

Next.js patches image caching, prefetch loops; Expo joins Claude connector directory

Next.js v16.3.1 fixes 0-byte disk cache entries, image optimization response preservation, and optimistic routing prefetch loops, while the Expo MCP server becomes a one-click Claude connector.

• —Next.js preserves optimized image responses and skips 0-byte disk cache entries during image optimization initialization.
• —Next.js resolves optimistic routing bugs that caused repeated prefetch loops, and restores live headers() views for dynamic pages.
• —Expo's MCP server is now listed in Claude's connector directory, enabling one-time sign-in setup for Claude web, desktop, mobile, and Claude Code.
• —SvelteKit trims noisy prerender progress output to only print newlines when needed.

Next.js and SvelteKit shift module boundaries

Next.js fixed stale post-revalidation data while SvelteKit's pre-release reorganized its public API surface, moving remote helper types into a dedicated module and RequestEvent/Cookies into `$app/server`.

• —Next.js fixes stale data appearing after revalidation and restores a live `headers()` view of the incoming request
• —SvelteKit 3.0 next releases move remote function types and `isValidationError` to `@sveltejs/kit/remote`, and `RequestEvent` and `Cookies` to `$app/server` — breaking import paths for those APIs
• —Svelte 5.56.9 streamlines hydration handling and prunes duplicated comments/whitespace in the compiled output