Third-party compat watch (2026-10-08): SvelteKit 3.0 and Preact 11 shipped; NestJS 12, Koa 3, Astro 7, React Router 8 are outside our tested ranges #11

Daily third-party compatibility check for the JS SDK. This is the first run, so it covers fresh releases from the last week plus gaps between what's published today and the ranges our adapters declare or test against.

New this week (act on these)

1. SvelteKit 3.0.0 is GA (Oct 1; latest is 3.0.1)

@bugsee/sveltekit dev-tests against @sveltejs/kit ^2.0.0. 3.0 is a large breaking major, and several changes land right on our handle / handleError seams:

• "run all errors through the handleError hook" (#16664) and "allow handleError to influence status code" (#16162): expect more (and different) errors through our hook, so dedup/filtering and status handling need a look.
• Hook types moved to @sveltejs/kit/hooks (#16737); handle's resolve is now always typed as a Promise (#16352).
• Tracing moved out of experimental and the instrumentation flag was removed (#16260), which matters for our trace propagation.
• $app/stores removed, Page moved to $app/state, getRequest/setResponse made synchronous, Server/SSRManifest dropped from public types.
• Floors went up: Node 22.17+, Vite ^8.0.12, Svelte 5.56.4+, TypeScript 6, @sveltejs/vite-plugin-svelte v7.

Release notes: https://github.com/sveltejs/kit/releases/tag/%40sveltejs%2Fkit%403.0.0

Suggested follow-up: add a Kit 3 leg to sveltekit-e2e and re-run @bugsee/sveltekit unit tests against @sveltejs/kit@3. Decide whether to support 2 and 3 side by side, then declare a peer range.

2. Preact 11.0.0 is GA (Sep 30)

There's no Preact adapter, but Preact is an explicit target (people run @bugsee/react through preact/compat). Changes that could affect us, from the upgrade guide:

• Shipped as ESM-only .mjs; the CJS/UMD bundles are gone.
• Hydration 2.0 uses comment markers for suspended and streamed boundaries, which could change what replay/rrweb sees in the DOM.
• Component.base removed, useEffect cleanup timing changed, refs forwarded by default, defaultProps and px auto-suffixing moved into preact/compat, SuspenseList removed.
• Browser floor is Chrome 71, Safari 12.1, Firefox 69; TypeScript 5.1+.

Release: https://github.com/preactjs/preact/releases/tag/11.0.0, blog post: https://preactjs.com/blog/preact-11

Suggested follow-up: smoke-test the React ErrorBoundary and router naming under preact/compat@11, plus a replay capture of a hydrated or suspended page.

3. Heads-up: Rollup 5.0.0-0 prerelease (Oct 6, beta tag)

This is the first prerelease of the next Rollup major. No changelog entry for it yet (the changelog only goes up to 4.64.2). It's relevant to bundler-plugin-core / vite-plugin source-map handling. Nothing to change yet; we'll keep watching for notes.

Existing gaps found on the first baseline

These aren't new this week, but published majors are already outside what we declare or test:

Also on the radar (prereleases, no action yet)

Electron 45.0.0-alpha.16, Fastify 6.0.0-alpha.4, Elysia 2.0.0-beta.26, Solid 2.0.0-rc.14 / @solidjs/router 2.0.0-next.36, Vue 3.6.0-rc.10, @opentelemetry/core and sdk-trace-base 3.0.0-development canaries, @opentelemetry/api 1.10.0-development canary.

Filed automatically by the Bugsee JS SDK third-party compatibility tracker (weekday check). Versions and dates come from the npm registry on 2026-10-08.