An update to Team Fortress 2 has been released. The update will be applied automatically when you restart Team Fortress 2. The major changes include: Added 64-bit support for Windows/Linux client and server Should include performance improvements for most users Bugs can be reported here: Fixed an exploit related to uploading invalid custom decals that would crash other clients
Maybe?
Lots of older games never get updated to 64-bit.
Besides the only operating system to not support 32bit code anymore is macOS, which even Valve treats as not worth bothering with anymore.