Windows 11 is basically based on same [https://en.wikipedia.org/wiki/Windows_NT NT 10.0 as Windows 10]. Mozilla tends to support EOL OS's for a couple years or longer after the Chrome/Chromium based browsers drop a OS version, especially Windows. For example Mozilla supported the then eol Windows XP/Vista for over two years longer compared to Chrome/Chromium based browsers (with Firefox 52.9.0esr being last). Mozilla is currently supporting the eol Windows 7, 8, 8.1 (and also macOS 10,12, 10.13, 10.14) with the older Firefox 115 ESR until Fx 115.21.0esr in March 2025 when Chrome/Chromium based browsers dropped 7, 8, 8.1 in Jan/Feb of 2023. Mozilla will be deciding in early 2025 on whether to extend updates for Fx 115 ESR again. https://support.mozilla.org/en-US/kb/firefox-users-windows-7-8-and-81-moving-extended-support