Valve has announced that as of January 1, 2024, Steam no longer officially supports the Windows 7, Windows 8, and Windows 8.1 operating systems. This means that the Steam Client running on PC hardware with these outdated Microsoft operating systems will no longer receive updates, including those focusing on security.
As for the reasoning, this isn't a decision spearheaded by Valve, as Steam relies on an embedded version of Google Chrome, "which no longer functions on older versions of Windows." In addition, future Steam Client updates will require features and security updates that are only available in Windows 10 and higher.
On that note, Microsoft ended its security updates for Windows 7 in January 2020, and Windows 8.1 security updates ended in January 2023. "Computers running these operating systems, when connected to the internet, are susceptible to new malware and other exploits which will not be patched," Valve writes in the Steam Support update.
This change won't affect a large percentage of Windows 7 and Windows 8 PC gamers, as the latest Steam Hardware and Software Survey results for December 2023 show that less than 1% of Steam users are rocking Windows 7 (0.74%) and Windows 8.1 (0.15%). Most Steam gamers run Windows 10 (53.45%), followed by Windows 11 (41.95%).
"In order to ensure continued operation of Steam and any games or other products purchased through Steam, users should update to a more recent version of Windows," Valve adds, stating that Steam will continue to work on Windows 7 and Windows 8.1 systems - though for how long remains to be seen. "We expect the Steam client and games on these older operating systems to continue running for some time without updates after January 1st, 2024, but we are unable to guarantee continued functionality after that date."