Have you looked to see if this latest will work? https://archive.mozilla.org/pub/firefox/releases/133.0.3/mac/

''<p>markwarner22 [[#answer-1694635|said]]</p>'' <blockquote>Have you looked to see if this latest will work? https://archive.mozilla.org/pub/firefox/releases/133.0.3/mac/ </blockquote> NO it will NOT work as Firefox 116.0 and later including Firefox 133.0.3 requires macOS 10.15 or later to run as the OP has macOS 10.11.6. https://www.mozilla.org/firefox/133.0.3/system-requirements/ I mentioned this to you a few times now.

''<p>giovannidigiorgi [[#question-1479184|said]]</p>'' <blockquote>Hello, I have an old version of MAC Os El Capitan 10.11.6, which new version of Mozilla can I install to respect new security standards ? Thanks for your help </blockquote> The last version to support the old macOS 10.9, 10.10, 10.11 was the old Firefox 78.15.0esr which you appear to have. https://support.mozilla.org/en-US/kb/firefox-mac-osx-users-esr Firefox 79.0 to 115.0 ESR requires macOS 10.12 (ten.twelve) at minimum to run. If you can upgrade your macOS to at least 10.12.x then you can use the still currently supported Firefox 115 ESR currently at 115.18.0esr and will be supported till at least 115.21.0esr in March 2025. https://support.mozilla.org/en-US/kb/firefox-users-macos-1012-1013-1014-moving-to-extended-support If you can upgrade to macOS 10.12 or later then you can download the Firefox 115.18.0esr.dmg from https://archive.mozilla.org/pub/firefox/releases/115.18.0esr/mac/ (will not run on macOS 10.11.6)