Except where noted, everything here applies to only to Firefox 102. Firefox 102 is the next ESR so, going forward, only bug fixes will be backported to the Firefox 91 ESR.

Bug Fixes

• Locking the preferences related to Deceptive Content and Dangerous Software Protection did not disable the user interface in about:preferences. This was fixed in bug 1568275 for both Firefox 102 and the Firefox 91 ESR.

Policies

• The ExemptDomainFileTypePairsFromFileTypeDownloadWarnings policy was added in bug 1722050. This policy allows you to disable warnings based on file extension for specific file types on domains. For example, you can remove the warnings when downloading and executing JNLP files.

• The UseSystemPrintDialog policy was added in bug 1770960. When this policy is enabled, Firefox will print using the system dialog by setting the preference print.prefer_system_dialog.

• The StartDownloadsInTempDirectory policy was added in bug 1738574. When this policy is enabled, Firefox will default to downloading files into a temporary directory and deleting them when the browser is closed (the old behavior). The new behavior was introduced in Firefox 93.

Special Notes

There are two more planned releases of Firefox 91 ESR and then it will go out of support on September 20, 2022. Users will then be automatically upgraded to the Firefox 102 ESR.