I need an older or a compatible version of firefox for mbo high serria 10.13.6

Firefox 115.34.0esr is the current compatible version for the EOL macOS 10.12, 10.13, 10.14 as Firefox 116.0 and later requires macOS 10.15 or later to run. The Firefox 115.34.0esr is based on the old Firefox 115.0 Release but with security/stability fixes since.

Thank You James, however that did'nt solve the problem. I did get a different version to try (140) which also did'nt work. Oh well.

I did get a different version to try (140) which also did'nt work. Oh well.

Like I said Firefox 116.0 and later including the current Fx 149.0 Release and Fx 140.9.0esr requires macOS 10.15 (ten.fifteen) or later to run.

There is a button to download the latest Firefox 115 ESR version on this page once you have selected OS and Language.

• https://www.mozilla.org/firefox/all/desktop-esr/