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Cypress v4.0.1stable Released Feb 08, 2020
Impact Score: 5/10

Cypress v4.0.1 — Release Notes & Engineering Impact

Source available — automated, not human-reviewed

Component: cypress · Channel: stable. Automated analysis, not a compatibility certification. How this works.

Analysis updated: 2026-11-01.

Compatibility not verified — check source notes
📄 .MD
⚡ Improvements 1 🔧 Bug Fixes 5
⚡ Executive Summary (TL;DR)

Cypress v4.0.1. Source highlight: Fixed a bug where Chromium could not be detected on macOS. Addresses #6358.

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Who Does This Impact? (Role-Based Analysis)

💻 Software Engineers & Devs

Check the source notes against the package and APIs you use before upgrading.

📊 Product & Engineering Leads

Use the documented changes to assess relevance to your product; release frequency alone is not a quality measure.

⚙️ DevOps & Security

Verify the target version, runtime requirements and rollback procedure in the official documentation.

⚡ Performance & Enhancements (1)

  • Updated the default preferences set on Firefox to hide update notifications and otherwise improve the Firefox experience. Addresses #6346.

🔧 Bug Fixes & Patches (5)

  • Fixed a bug where Chromium could not be detected on macOS. Addresses #6358.
  • Fixed bugs where Edge and Firefox Nightly could not be detected on macOS. Addresses #6354 and #6345.
  • Fixed a bug where 64-bit editions of Firefox could not be detected on Windows. Addresses #6355.
  • Fixed a bug where video recordings of Firefox would omit all frames from before the last cross-domain navigation of the test. Addresses #6369.
  • Fixed a bug where Cypress could crash with the message "cannot read property 'on' of undefined" while running Firefox. Addresses #6356.
📄 View Raw Release Notes (Original Developer Log)
*Released 2/7/2020* **Bugfixes:** - Fixed a bug where Chromium could not be detected on macOS. Addresses [#6358](https://github.com/cypress-io/cypress/issues/6358). - Fixed bugs where Edge and Firefox Nightly could not be detected on macOS. Addresses [#6354](https://github.com/cypress-io/cypress/issues/6354) and [#6345](https://github.com/cypress-io/cypress/issues/6345). - Fixed a bug where 64-bit editions of Firefox could not be detected on Windows. Addresses [#6355](https://github.com/cypress-io/cypress/issues/6355). - Fixed a bug where video recordings of Firefox would omit all frames from before the last cross-domain navigation of the test. Addresses [#6369](https://github.com/cypress-io/cypress/issues/6369). - Fixed a bug where Cypress could crash with the message "cannot read property 'on' of undefined" while running Firefox. Addresses [#6356](https://github.com/cypress-io/cypress/issues/6356). - Corrected a link to the screenshot API documentation in the type definitions. Addresses [#6359](https://github.com/cypress-io/cypress/issues/6359). **Misc:** - Updated the default preferences set on Firefox to hide update notifications and otherwise improve the Firefox experience. Addresses [#6346](https://github.com/cypress-io/cypress/issues/6346).
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