Release Engineering

Pale Moon is released on a 1-2 month release cycle (other applications built from the Unified XUL Platform may be released with a difference cadence).

The Release Cycle

Historically, we retained Application and Platform release timings mostly in tandem with Firefox to evaluate any Mozilla security fixes included in their releases. However, as Mozilla kept speeding up their release cycle to eventually land on an impossibly fast 2-week churn for new versions (one might think they have not looked closely at how Agile development systems do not work in practice...), we have decoupled from a strict calendar-based release cycle once more as fewer and fewer security issues, which have been the main driver for our releases somewhat in tandem, are actually applicable to the more mature and less experimental code base of UXP.

Pale Moon will primarily be alternating between the type of release, with a Major/Feature release and then one or more Minor/Security releases. However, real world factors in tangible development may alter the intended cycle. Be sure to check announcements made for such changes.

Version numbers and release types

The current Pale Moon version scheme is: [Milestone].[Major/Feature].[Minor/Security] with a fourth version point being reserved for [Out-of-band] releases. Each of these version points corresponds with a type of release for Pale Moon.

Release Type	Description
Milestone	A significant release that may include an abundance of new features and backward-incompatible changes.
Major/Feature	A release which includes new and updated features with or without minor backward-incompatible changes.
Minor/Security	A release with minor changes, bug fixes, and applicable security patches.
Out-of-band	An unscheduled release that resolves critical items on an ad-hoc basis.

NOTE: All release types MAY and often DO contain applicable security patches. For your safety it is recommend that you always stay up to date.

While we identify all UXP stable releases by date and the above types, we also still maintain an internal version number. This "mozilla milestone" version is not currently hard-defined according to any current scheme and should NOT be relied on for anything.

Current planned release schedule for Pale Moon

Our releases are less predictable by specific calendar days, and rely more on when specific features are completed and tested than a rigid schedule. As such, it is difficult to outline the anticipated release schedule but this page may be updated if there are known upcoming releases or milestones.

Pale Moon Version	Closed tree	Intended Release Date	Type of Release
v34.3.2	2026-07-26	2026-08-04	Minor/Security Release
v35.0.0	TBD	TBD	Development Release

Previous releases of Pale Moon and the Unified XUL Platform

Please refer to the Pale Moon release notes (or archived ones for older releases) and tagged UXP/Pale Moon commits in the repository for previous releases.

The Release Workflow

Our release engineering workflow happens over the course of one week starting with a "code freeze" which tends to always be a Tuesday and will run through the week to the following Tuesday which is our release day.

• Tuesday - Code Freeze
  • The master branches will be placed under a "Closed Tree" type of condition where no high-risk patches and feature merges will be permitted until after merge day.
• Tuesday through Friday - Security Updates
  • Each known Mozilla security vulnerability from the previous release to the current day will be evaluated and patched, if applicable.
• Friday - Release Branch Preparations (Merge Day)
  • For Major/Development Releases: The master branches will be merged to the release branches.
  • For Minor/Security Releases: The security patches and any minor patches will be cherry-picked to the release branch(es).
  • Application Release Notes will be drafted.
• Friday through Monday - Build and Test Release Candidates
  • Build signed binaries for various target operating systems and make them available for final acceptance tests (Release Candidates).
  • Test built binaries for any show-stoppers. Implement spot-fixes or back-out problematic code changes that are too big to tackle on short notice. Building new binaries (RC2, 3, etc.) as-needed.
• Monday-Tuesday - Finalize Releases
  • Distribute final binaries to release mirrors.
  • For Major Releases: Finalize language packs (download from CrowdIn and process).
  • Write/edit final Application Release Notes.
• Tuesday - Release Day
  • For Major Releases: Update language packs on the add-ons site.
  • Put web pages live, enable new downloads, update the automatic update service.
  • Publish announcements on forum and to any applicable other sites/services.
  • Update the Microsoft Store packages and queue for their review.