Firefox 152 release notes for enterprise admins

Firefox 152

Released 16 June 2026.

These changes apply to Firefox 152 unless explicitly stated. Firefox ESR 140.12.0 shipped the same day, but most of these changes were not backported to it.

Changes

DefaultSerialGuardSetting: Web Serial support is now disabled by default when Firefox is managed by enterprise policies.
ExtensionSettings: Force-installed extensions are now always updated automatically, regardless of the updates_disabled setting. (bug 2037243)
FirefoxHome: Allow configuration of the Weather experience. Also in Firefox ESR 140.12.0.
ManagedBookmarks: Allow specifying favicons directly for managed bookmarks.
Chatbot content is now available to extensions from content scripts. (bug 1980404)
Firefox now accepts TURN server responses whose XOR-MAPPED-ADDRESS does not match the ICE check, improving compatibility with some TURN server implementations. (bug 2034159)

Fixes

DisableBuiltinPDFViewer: Setting the policy to false overrode the PDF handling configured in handlers.json. Also in Firefox ESR 140.12.0. (bug 1983032)
DisableFirefoxAccounts: The policy also disabled Backup and other unrelated settings after the Settings redesign. (bug 2023825)
DisableProfileImport: The Import Bookmarks button on the Bookmarks Toolbar bypassed the policy. (bug 1828282)
DisableProfileImport: The import option in about:logins was not covered by the policy. (bug 1830463)