Except where noted, everything here applies to both Firefox 131 and the Firefox 128.3 ESR. Firefox 128 is the current standard ESR so, going forward, no enterprise changes will be backported to Firefox 115 ESR.

Bug Fixes

• Setting UseHTTPProxyForAllProtocols in the Proxy policy incorrectly set the SOCKS host. This was fixed in bug 1919318.

Policies

• The PrivateBrowsingModeAvailability policy was added to the Firefox ESR.

Other Changes

• We now support single sign-on for Microsoft Entra accounts on macOS. Currently you can set a pref to enable it (network.http.microsoft-entra-sso.enabled). This change is only in Firefox 131. A policy to enable this will be in Firefox 132 and Firefox ESR support will be in 128.4.

Special Notes

Firefox 115 ESR goes out of support for enterprises with this release. Firefox 115 ESR users will be upgraded to the Firefox 128 ESR.

We are extending Firefox 115 ESR support for Windows 7/8 and macOS 10.12/10.13/10.14 users until March 2025.

If you need to prevent upgrades for any reason, you can use the AppUpdatePin policy.