Firefox 116.0 and later requires Windows 10, 11 to run. https://support.mozilla.org/en-US/kb/firefox-users-windows-7-8-and-81-moving-extended-support Windows 7, 8, 8.1 (and macOS 10.12, 10.13, 10.14) is still being supported with the older Firefox 115 ESR channel. It is currently at Fx 115.21.0esr (released March 4) and will be updated till Fx 115.27.0esr in August unless Mozilla extends the security/stability updates again. You appear you have a version of Firefox 115 ESR installed on Windows 7. Thunderbird is off-topic for this section however the last update to support the eol Windows 7, 8, 8.1 was Tb 115.18.0. Not user if you use 64-bit or 32-bit Windows 7 and pick the language folder you want. https://archive.mozilla.org/pub/thunderbird/releases/115.18.0/win64/ https://archive.mozilla.org/pub/thunderbird/releases/115.18.0/win32/