Hi, It is OK to continue using this version, but sync option is going to be disabled. Everything else stays as it was.

''<p>timr123 [[#question-1440613|said]]</p>'' <blockquote>I’m being advised via emails from Mozilla, to update my browser. It says it’s up to date. A cut off of 31 March has been stated. My mbp won’t run higher than OS X 10.11.6. Firefox 78.15.0esr the latest browser for my system..afaik. I am on the ESR update channel, and think it updates automatically. Am I being left high & dry by Mozilla? Something in the emails about syncing…? Not convinced if this is something I should be doing something about or not… </blockquote> The email is to inform you that Sync is no longer being supported in the old Firefox 78.0 and earlier versions as you will need 79.0 or later to use Sync. https://support.mozilla.org/en-US/kb/sync Firefox 78.15.0esr was the last update that supports your old macOS 10.11 so no more Firefox updates has occurred since. The old Firefox 78.15.0esr you have will still work the same as it does now minus not being able to use the Sync feature so you are not being left high and dry. The Firefox 78.15.0esr is the most current web browser you can use for the old EOL macOS 10.11 however over time websites may not display properly or insist you use a more current version of Firefox to use site properly. Firefox 78.15.0esr is the latest to still support the old EOL macOS 10.9, 10.10, 10.11 https://support.mozilla.org/en-US/kb/firefox-mac-osx-users-esr Firefox 79.0 to 115 ESR requires macOS 10.12 (ten.twelve), 10.13, 10.14 at minimum to run. https://support.mozilla.org/en-US/kb/firefox-users-macos-1012-1013-1014-moving-to-extended-support Firefox 116.0 and later requires macOS 10.15 (ten.fifteen) or later to run. If you can update to at least macOS 10.12 (ten.twelve) then you can use the still supported Fx 115 ESR (currently at 115.8.0esr) as the last update 115..15.0esr will be in Sept 2024. https://www.mozilla.org/firefox/all/#product-desktop-esr (<--requires macOS 10.12 or later as it will not run on your 10.11)

So what exactly is it that I need to spin up locally to keep the sync working on 78? The accounts service + the sync service? Old one (python) or the new one (rust), or either would work?