26 March, 2026

This release upgrades TypeScript to version 6 and updates core dependencies used by your custom functions and tests.

TypeScript 6

We've upgraded from TypeScript 5.8 to TypeScript 6.0. This is a major version bump that may surface new type errors in your existing function, subscriber, and job code.

Keel automatically updates your tsconfig.json with the required compiler options to ease the transition:

• ignoreDeprecations: "6.0" is added for backward compatibility with deprecated compiler options
• noImplicitAny: false is set because TypeScript 6 enables this by default, which would flag errors in code without explicit type annotations. You can opt in to stricter checking by setting this to true.
• target and lib are upgraded from ES2016 to ES2022, enabling modern JavaScript APIs like Array.at() and Object.hasOwn()

If you encounter new type errors after upgrading, these are likely caused by stricter checks in TypeScript 6. We recommend working through them as they represent genuine improvements to type safety.

Updated Node.js Requirements

The minimum supported Node.js version has changed. Keel now requires:

• Node.js >=20.19.0 (but less than 21), or
• Node.js >=22.12.0

If you're running an older version, you'll see an error when starting Keel. We recommend upgrading to the latest Node.js 22 LTS.

Vitest 4

Tests now run on Vitest 4 (upgraded from 3.1). The vite-tsconfig-paths plugin has been replaced with Vite's native resolve.tsconfigPaths and will be automatically removed from your project.

Fixes and Improvements

For a full list of fixes and improvements, check out our GitHub releases page (opens in a new tab).

For any issues or feedback, please contact us at help@keel.so.

Thank you for using Keel!