Add Firefox ESR (Extended Support Release) support statement for latest release

[MikeMcC399]

Description

What would you like?

Include an official statement of support by Cypress for the latest Firefox ESR (Extended Support Release), in addition to the latest 3 major versions from the Firefox Rapid Release channel.

Why is this needed?

Firefox ESR is the only stable Firefox release which supports both the Linux/amd64 the Linux/arm64 platforms on Debian-based distributions. Cypress Docker images are based on Debian 12 which includes Firefox ESR as its default browser: for instance Debian 12.9 includes Firefox ESR 128.6.0esr.

References > Lauching Browsers > Browser versions supported currently states:

Cypress officially supports the latest 3 major versions of Chrome, Firefox, and Edge. (For example, if the stable release of Chrome was 130, Cypress would officially support Chrome 128, 129, and 130.)

The current latest major version of Firefox is 134. See https://www.mozilla.org/en-US/firefox/134.0.1/releasenotes/

So, according to the Cypress text above, Firefox 132, 133 and 134 would be supported by Cypress.

The latest Firefox ESR version is however 128, which is outside the rule covered by "latest 3 major versions". See https://www.mozilla.org/en-US/firefox/organizations/notes/.

Although Cypress 14 runs successfully against Firefox 128 ESR on Debian, according to the documentation, it is not officially supported by Cypress.

Other

Choosing a Firefox update channel explains the Firefox "Extended Support Release (ESR)" and compares it to the "Rapid Release" channel.

Extended Support Release (ESR): receives major updates on average every 52 weeks with minor updates such as crash fixes, security fixes and policy updates as needed, but at least every four weeks.

Debian 12 test

On Debian 12.9 amd64, Node.js 22.13.0 LTS, the following test runs successfully, so I assume that adding support for Firefox ESR is a documentation change only and that it does not need a feature request in the https://github.com/cypress-io/cypress repo:

sudo apt-get update && sudo apt-get install firefox-esr -y

git clone https://github.com/cypress-io/cypress-docker-images
cd cypress-docker-images
cd examples/firefox-esr

npm install cypress@14 -D
npx cypress info
npx cypress run --browser firefox