These changes apply to Firefox 152. Where a change also applies to Firefox 140.12 ESR, it will be noted explicitly.

Firefox 140 is the current ESR, and Firefox 153 will be the next ESR release. Organizations using Firefox ESR should begin testing with Firefox Beta or Nightly to identify any deployment issues before the transition.

Mozilla has introduced Firefox Support for Organizations, a new support offering for enterprise deployments of Firefox. For more information, see this blog post.

Bug Fixes

• The DisableProfileImport policy was bypassed by the Import Bookmarks button on the Bookmarks Toolbar. This was fixed in bug 1828282.
• The DisableProfileImport policy was not enforced on the import option available from about:logins. This was fixed in bug 1830463.
• The DisableBuiltinPDFViewer policy could override PDF handling preferences configured through handlers.json even when set to false. This was fixed in bug 1983032. This was also fixed in Firefox 140.12 ESR.
• Extensions that were force-installed by enterprise policy could have updates disabled. This was fixed in bug 2037243.

Other Changes

• WebExtensions can now access chatbot content from content scripts. This was implemented in bug 1980404.
• Firefox now accepts certain TURN server responses that were previously rejected. This improves compatibility with some TURN server implementations. This was fixed in bug 2034159.

Policies

• The FirefoxHome policy has been updated to allow configuration of the Weather experience.
• The ExtensionSettings policy has been updated to prevent users from disabling extension updates.
• The DefaultSerialGuardSetting policy has been added to control access to the Web Serial API.
• Web Serial support is now disabled by default when Firefox is managed by enterprise policies.
• The ManagedBookmarks policy has been updated to allow specifying favicons directly for managed bookmarks.

Special Notes

We are extending Firefox 115 ESR support for Windows 7/8 and macOS 10.12/10.13/10.14 users until August 2026.