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Firefox and Firefox Extended Support Release (ESR)

Firefox is made available in multiple versions known as release channels. This article describes the difference between the channels and the tradeoffs to consider when choosing one. The two channels that are most appropriate for enterprise usage are Firefox and Firefox Extended Support Release (ESR).

The Firefox release channel is primarily used by consumers, but it is also applicable as an enterprise browser. A new major (semver) version is made available every four weeks. Releases include new features, enhancements, and bug fixes.

The following resources are useful for tracking what's changed in Firefox releases:

  • Firefox releases: details on the features and fixes improve everyday browsing.
  • Firefox release notes for developers: these release notes describe developer-facing changes. This contains details on new or updated web platform features, APIs, and tools that developers use.

New versions of ESR are released annually. After release, each ESR version receives incremental security updates as minor or patch release versions (major.minor.patch). Other features, such as UI or UX improvements, are excluded from the ESR channel, and are limited to annual ESR releases.

Detailed information about the release schedule for Firefox can be tracked on whattrainisitnow. This website provides a release calendar that describes upcoming releases for all Firefox release channels.