Firefox ESR
Release Notes

Firefox Quantum arrives in the ESR channel. Key features include:

• A completely new browser engine, designed to take full advantage of the processing power in modern devices
• A redesigned interface with a clean, modern appearance, consistent visual elements, and optimizations for touch screens
• A unified address and search bar. New installs will see this unified bar. Learn how to add the stand-alone search bar to the toolbar
• A revamped new tab page that includes top visited sites, recently visited pages, and recommendations from Pocket (in the US, Canada, and Germany)
• An updated product tour to orient new and returning Firefox users

Support for enterprise environments, with a policy engine that allows customized Firefox deployments using Windows Group Policy or a cross-platform JSON file

Firefox now exclusively supports extensions built using the WebExtension API. Unsupported legacy extensions will no longer work in Firefox 60 ESR, but they will continue to work in Firefox 52 ESR, which will be supported until September 2018. Learn more about our efforts to improve the performance and security of extensions

TLS certificates issued by Symantec before June 1st, 2016 are no longer trusted by Firefox. The "security.pki.distrust_ca_policy" preference can be set to 0 to reinstate trust in those certificates

Service workers and push notifications remain disabled in Firefox ESR

In Firefox 58 and later, and in Firefox 60 ESR and later, Firefox uses a new format for storing private keys, certificates and certificate trust

• Users who store their home directory or application data directory on a network filesystem are advised to set the environment variable NSS_SDB_USE_CACHE=yes prior to starting Firefox
• Without setting this environment variable, users of network filesystems may experience a major slowdown when starting and using Firefox
• The environment variable enables the use of a caching strategy in NSS that works around the slowness of network filesystems. Because this caching strategy causes a performance decrease on fast filesystems, it isn't used by default, but requires users to explicitly enable it by setting the environment variable