Windows 7 & Windows 8
According to a recent Steam announcement, the game platform will no longer support Windows 7, Windows 8, and Windows 8.1 after January 1, 2024, due to core features relying on an embedded version of Google Chrome that no longer functions on older versions of Windows. Users must update to a more recent version of Windows to continue running Steam and any games or other products purchased through Steam.
Microsoft has already ended security updates and technical support for Windows 7 and will end support for Windows 8.1 in January 2023, leaving computers running these operating systems susceptible to new malware and other exploits that will not be patched.
Source: Steam