Firefox Nightly or Beta, are affected by Mozilla's decision to end support. It is unclear if and how other Firefox channel installations, e.g. The latest Firefox version includes security updates so downgrading to an older version leaves you more vulnerable to attacks and usually doesn't fix the problem. If there is a problem with a new version of Firefox, some people may want to downgrade Firefox to a previous version but we do not recommend this. Firefox 49 was released on Septemfor both desktop and Android. Additionally, support for old processors without SSE2 extensions such as the AMD Athlon XP and Pentium III was dropped. Mac OS X users of Firefox who still use these older versions of the Mac OS X operating system will be able to use Firefox ESR for another year before support runs out. If you install an older version, you'll be prompted to create a new Firefox profile. Firefox 48 is the last Firefox version to support Mac OS X Snow Leopard, Mac OS X Lion, and OS X Mountain Lion. We're looking at moving users on versions < 10.12 to the esr branch with the release of Firefox 78, to both be able to support them for about a year longer, and reduce the burden from old versions on engineering and QA for mainline Firefox.Ī meta bug has been created on Bugzilla that tracks the migration process.
We currently support macOS versions 10.9 to 10.15. Why is that done? Mozilla notes on Bugzilla: Mozilla plans to end support for Mac OS 10.9 to 10.11 (Mac OS X Mavericks, Yosemite, and El Capitan) next year Firefox Stable installations on these systems will be migrated to Firefox ESR 78 when the new version is released on June 30, 2020. The release of Firefox 78 and Firefox ESR 78 changes that.
