Phoenix 2026.05.21.1

This can likely be considered one of the most significant Phoenix releases since the project's inception. It includes a major restructure of how Phoenix functions and configures its preferences, and significantly improves the overall functionality/utility that Phoenix can provide (made possible by recent upstream efforts that allow us to configure Phoenix in the same standard .cfg format across all major desktop platforms).

Notably, one of the major additions of this release is the introduction of Phoenix-specific preferences to configure certain behavior. These preferences are detailed at the Preferences documentation page, but more information on some of the notable ones can be found below.

Changes

• Phoenix releases/archives are now directly uploaded to/distributed via https://releases.celenity.dev (links provided as external assets below), providing greater control and improving reliability/accessibility for users.
• In order to improve privacy and help circumvent censorship, Phoenix will now automatically set the DNS over HTTPS (DoH) bootstrap address for supported (built-in) DoH providers.
  • This functionality is enabled by default, but can be disabled with the newly added browser.phoenix.trr.autoBootstrap preference.
  • In the event of network connectivity issues, users can instead set Phoenix to use the secondary bootstrap address for supported providers, with the browser.phoenix.trr.autoBootstrap.useFallback preference (Disabled by default).
  • Note that a restart is required for changes to take effect after modifying the values of browser.phoenix.trr.autoBootstrap and/or browser.phoenix.trr.autoBootstrap.useFallback.
  • Note that when browser.phoenix.trr.autoBootstrap is enabled (set to true), a restart will also be required upon changing DoH providers in many cases.
• Users can now toggle Phoenix Extended by simply navigating to about:config, setting browser.phoenix.extended to true, and restarting the browser. Set-up of additional external files is no longer required!
  • Current users of Phoenix Extended via the specialized config approach will be automatically migrated to the new method, though it is recommended to remove and/or update the user.js file you are using to apply it. After doing so and restarting the browser, it is additionally recommended to set browser.phoenix.usingLegacySpecConfig to false at about:config, to prevent future issues/unnecessary complications.
• Instead of modifying the privacy.fingerprintingProtection.overrides preference directly, users should now specify global FPP overrides at browser.phoenix.fingerprintingProtection.global.userOverrides instead. This was added as it allows users to add their own overrides, without needing to override Phoenix's default overrides (unless desired by the user).
  • Note that a restart is required for changes to take effect after modifying the value of browser.phoenix.fingerprintingProtection.global.userOverrides.
  • An example of the syntax for this preference can be seen at browser.phoenix.fingerprintingProtection.global.userOverrides.0.example.
  • Overrides set by current Phoenix users via privacy.fingerprintingProtection.overrides will be automatically migrated to the browser.phoenix.fingerprintingProtection.global.userOverrides preference, though be sure to remove any duplicate/redundant targets from the value of browser.phoenix.fingerprintingProtection.global.userOverrides if present.
• Instead of modifying the privacy.fingerprintingProtection.granularOverrides preference directly, users should now specify granular (per-site) FPP overrides at browser.phoenix.fingerprintingProtection.granular.userOverrides instead. This was added as it allows users to add their own overrides, without needing to override Phoenix's default overrides (unless desired by the user).
  • Note that a restart is required for changes to take effect after modifying the value of browser.phoenix.fingerprintingProtection.granular.userOverrides.
  • An example of the syntax for this preference can be seen at browser.phoenix.fingerprintingProtection.granular.userOverrides.0.example.
  • Overrides set by current Phoenix users via privacy.fingerprintingProtection.granularOverrides will continue to take effect, as they will be migrated to the browser.phoenix.fingerprintingProtection.granular.legacyUserOverrides preference. It is strongly encouraged to migrate your currently set overrides from browser.phoenix.fingerprintingProtection.granular.legacyUserOverrides to the new browser.phoenix.fingerprintingProtection.granular.userOverrides preference/format (Notably: Ensure you do not include [] surrounding your value(s)), and to remove any duplicate/redundant entries if present. Be sure to clear the value of browser.phoenix.fingerprintingProtection.granular.legacyUserOverrides once you are done migrating your overrides to browser.phoenix.fingerprintingProtection.granular.userOverrides.
• Added a preference (browser.phoenix.fingerprintingProtection.granular.unbreakOverrides.enabled) to control whether Phoenix's default granular (per-site) FPP overrides to relax protections for certain websites (in order to resolve breakage and unexpected behavior) are applied.
  • Note that a restart is required for changes to take effect after modifying the value of browser.phoenix.fingerprintingProtection.granular.unbreakOverrides.enabled.
• Added a preference (browser.phoenix.fingerprintingProtection.granular.unbreakTimezoneOverrides.enabled) to control whether Phoenix's default granular (per-site) FPP overrides to disable timezone spoofing (if timezone spoofing is active) for certain websites (in order to resolve breakage and unexpected behavior) are applied.
  • Note that a restart is required for changes to take effect after modifying the value of browser.phoenix.fingerprintingProtection.granular.unbreakTimezoneOverrides.enabled.
• Switched the default search engines back to GET, due to bugs/issues experienced by users.
  • A separate POST variant for each default search engine is still included for users who desire the added privacy and security, at the cost of breakage/issues in certain cases.
• Disabled keyboard locking by default to prevent websites from being able to hijack browser/OS-level key combinations.
  • Thanks to degausser! 💜
• Disabled the Document Picture-in-Picture API by default.
  • Thanks to degausser! 💜
• Disabled WebGPU for PDF.js by default.
• Re-enabled the File System API by default, in order to prevent breakage on certain sites.
• Updated the URL query parameter stripping list (per Brave's latest changes).
  • Thanks to any1here! 💜
• Disabled newly added Mozilla nags/promotions.
• Cleaned-up certain old/unused preferences.
• Other minor tweaks, fixes, and enhancements.

Android-only

• Removed profile.accounts.firefox.com from the internal domain blocklist, due to it breaking Firefox Sync-related UI.

Desktop-only

• Disabled display of favicons for remote tabs (from Firefox Sync) by default to prevent unsolicited network connections.
• Enabled support for Mozilla IP Protection by default, due to it being free to use and improving the privacy of users.
• Disabled Mozilla VPN ads/promotions.
• Added the UserMessaging -> FirefoxLabs enterprise policy to disable Firefox Labs (as the preferences used to control it previously have been removed, and Firefox Labs relies on Nimbus so it didn't function for us anyways - it simply resulted in broken Firefox Labs sections appearing at about:preferences).

Specialized Configs

• Phoenix's specialized configs are now set from one configuration file, instead of requiring a separate configuration file for each config.
  • Current users of specialized configs will be automatically migrated to the new mechanism, though it is recommended to remove and/or update the user.js file you are using to apply your specialized config(s) of choice. After doing so and restarting the browser, it is additionally recommended to set browser.phoenix.usingLegacySpecConfig to false at about:config, to prevent future issues/unnecessary complications.
• The welcome message on initial set-up/installation is now displayed directly, instead of it requiring/being read from a separate file.

Codeberg: See here for more details.

GitLab: See here for more details.

GitHub: See here for more details.

:)