Meteor 3.5.2-beta.0: Rspack reliability, Cordova Android 15, and DDP connection fixes

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Meteor 3.5 introduced MongoDB Change Streams, DDP session resumption, pluggable transports, and Node.js 24. Meteor 3.5.1 then strengthened Meteor runtime, Rspack and reconnection behavior.

Meteor 3.5.2-beta.0 continues that reliability work by refining Rspack builds, updating the Cordova Android toolchain, strengthening runtime defaults, and addressing community reports and reproductions.

Please test this beta in development or staging, especially if your application uses Rspack, Cordova, HttpOnly cookies, custom MongoDB TLS settings, or a large local package warehouse. Your feedback will help us catch regressions across real-world projects and deliver a more reliable Meteor 3.5.2 stable release.

Getting Started

Create a New App


meteor create my-app --release 3.5.2-beta.0

Update Your App


meteor update --release 3.5.2-beta.0

As with every beta, test before updating production applications and keep current project and database backups.

Highlights

Rspack and build tooling

  • Full-app tests preserve top-level await and build the correct client and server bundles (PRs #14405, #14643, #14653, and #14678).

  • Development, test, and app-test builds are isolated when they share an application directory (PRs #14576 and #14678).

  • Persistent caches stay valid across modes, TypeScript configuration changes invalidate the right work, and linker caches are cleaned correctly (PRs #14569, #14645, and #14646).

  • Meteor resolves hoisted Rspack CLI installations, limits ignored-extension scanning, loads SWC only when needed, and fails immediately if Rspack exits before its first compilation (PRs #14578, #14581, #14641, and #14643).

  • The new tools-core dependency manager streamlines setup by installing required Rspack npm dependencies automatically (PR #14492).

Thank you to @ToyboxZach, @jdgjsag67251, @MaxTwentythree, and @Nefleex for detailed reports and reproductions. We also thank @perbergland and @miamagana for their investigations and proposed fixes, and @hexsprite and @vlasky for implementing and validating the bundle, cache, watcher, and startup improvements.

These improvements ship through rspack@1.3.0-beta352.0 and @meteorjs/rspack@2.2.0-beta.0.

:link: Meteor Rspack integration guide

Cordova and Android

:link: Meteor Cordova guide

Runtime security and MongoDB

  • HttpOnly cookie endpoints are exposed only when useHttpOnlyCookies is enabled, and oversized request bodies are rejected (PR #14657).

  • Invalid MONGO_URL warnings redact credentials, and startup compatibility checks respect connection-string TLS settings (PR #14658).

Thank you to @italojs for these security and diagnostics improvements.

DDP and client integrity

  • DDP follows the browser page protocol when deriving its default connection URL, preventing mismatches between the page and ROOT_URL (PR #14640). Thank you to @dupontbertrand.

  • Client manifest sizes, hashes, and SRI values now match the exact bytes written to disk after source-map URL processing (PR #14482). Thank you to @mitar for the original report and reproduction.

File watching and package testing

  • Meteor no longer watches immutable package warehouse files, reducing native watcher usage and preventing macOS FSEvent exhaustion (PR #14672). Thank you to @hexsprite.

  • test-in-browser no longer supplies jQuery transitively, allowing Blaze tests to run with or without jQuery when it is declared explicitly (PR #14308). Thank you to @jankapunkt.

What Else Is New in Meteor 3.5.2-beta.0?

Breaking Changes

Meteor patch releases normally avoid breaking changes. These two migration steps are intentionally narrow: one keeps Cordova Android builds aligned with an external platform requirement, and the other corrects an implicit test-only dependency. Most Meteor applications are unaffected.

  • Cordova Android only. cordova-android@15.1.0 targets API 36 so apps can meet Google Play’s annual target API policy. This requires Android SDK Platform 36 and Build Tools 36.0.0, but only projects that build for Cordova Android need to act (PR #14487).

sdkmanager 'platforms;android-36' 'build-tools;36.0.0'
  • Tests relying on implicit jQuery only. test-in-browser@1.6.0-beta352.0 no longer supplies jQuery transitively. This makes the dependency explicit and lets Blaze test its jQuery-free path. Application runtime code is unaffected; test suites that need jQuery must declare it or run with --extra-packages=jquery (PR #14308).

This beta also includes more improvements and package updates. See the Meteor 3.5.2 changelog for the full details, or review the pull requests merged into release-3.5.2 through beta.0 for the complete implementation history.

Big Thanks to Our Contributors and Sponsors

Thank you to @nachocodoner, @italojs, @Grubba27, @hexsprite, @dupontbertrand, @jankapunkt, @vlasky, @perbergland, @miamagana, @a4xrbj1, @boomfly, @harryadel, @9Morello, and @zodern for authoring, contributing to, and reviewing this release.

We also thank @mt-resos, @koad, @ToyboxZach, @mitar, @MaxTwentythree, @Nefleex, @jdgjsag67251, @julio-rocketchat, @scharf, and @nico014 for reporting issues and developing reproducible test cases.

Meteor’s continued modernization also depends on sponsors who make long-term investment in the framework possible. Thank you to our current sponsors: Galaxy, Input Logic, and CodeRabbit.

If Meteor has helped you build and grow, consider supporting what comes next through the Meteor Sponsorship Program.

What’s Next for Meteor and Beyond?

After Meteor 3.5.2 stabilizes, our next focus is taking Meteor 3.6 from beta to its official release.

  • Meteor 3.5.2 stabilization. Validate the beta across supported platforms, address regressions, and prepare the official release. Targeting Meteor 3.5.2 stable within a three-week cycle.

  • Built-in TypeScript. Deliver a solid integration for Meteor projects, with full Atmosphere package coverage. Planned for Meteor 3.6.

  • Rspack 2.x. Upgrade Rspack and continue refining the bundler integration. Planned for Meteor 3.6.

  • Node 26 and CLI. Include further Node.js and Meteor CLI improvements. Planned for Meteor 3.6.

  • CapacitorJS experimentation. Try Meteor’s modern native stack now through the experimental Meteor checkout. A public experimental beta may arrive during Meteor 3.6, with a stronger native focus planned for Meteor 3.7.

For more details on upcoming work and priorities, see the Meteor roadmap.

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