https://support.mozilla.org/en-US/kb/firefox-users-windows-7-8-and-81-moving-extended-support

Let me guess you are running the old eol Windows 7, 8, or 8.1 and as a result the latest Firefox version you can run is Firefox 115 ESR currently at 115.29.0esr and planned for updates till 115.33.0esr next year unless Mozilla extends again.

In order to run Firefox 116.0 and later including the current 144,0.2 Release and current 140.4.0esr you need Windows 10, 11.

If you actually have Windows 10 or 11 then you may be running Firefox in Windows 8 compatibility mode for some reason.

If you are stuck with Windows 7, 8, 8.1 then you may be able to trick the chase site into thinking you have a more later version of Firefox.

1. In a new tab, type or paste about:config (with a colon) in the location (address) bar and press Enter/Return. Click the button accepting the risk.
2. In the search box in the page, type or paste forceVersion and pause while the list is filtered
3. Double-click the network.http.useragent.forceVersion preference to display an editing field, and change the value to 128 or 140 then press Enter/Return or click the blue check mark button to save the change.