Amid the E3 hubbub this week Valve posted a brief note warning people that Steam support for Windows XP and Vista is depreciating, and the online game platform will no longer run on the two operating systems by January 1st, 2019.
Other than signifiying the passing of an age, this doesn't seem like a big deal for devs, given that fewer than one percent of the Windows users polled by Steam's May 2018 Hardware & Software Survey were using either Windows XP or Vista.
Still, it's something worth noting if for some reason you happen to still be running XP or Vista on anything. According to Valve, Steam is moving away from the two ancient OSes for both security and service reasons, and some of Steam's new features (like the new chat system) already don't work on XP or Vista.
"The newest features in Steam rely on an embedded version of Google Chrome, which no longer functions on older versions of Windows," reads Valve's note. "In addition, future versions of Steam will require Windows feature and security updates only present in Windows 7 and above."
After January 1st, Steam will no longer run on XP or Vista, and so anyone who owns your games through Steam and runs either OS will have to upgrade.