After a long period of time with Beta releases, which brought with it some important new features, especially for Linux gamers, Valve has finally released yet another stable update for the Steam client that brings several improvements for those players running their games with Proton compatibility layer.
Among the highlights is support for CEG DRM, allowing many more Windows games to run with Proton/Steam Play. However, you currently still need to be using Proton Experimental, at least until Proton 6.3-8 is released, but as of this writing, it is still in the testing phase.
Other specific improvements that should benefit Linux gamers include "scout" and "heavy" runtimes, allowing better compatibility with recent Let's Encrypt TLS/SSL certificate chains, a boot failure fix has also been added for experimental versions of Mesa (library that brings together the most varied video drivers for Linux). The "Shader Pre-Caching" feature also had improved performance and disk usage was reduced when updating Mesa caches on Linux.
Last but not least, hardware encoding via Video Acceleration API (VA-API) is now supported, with an option to turn it off if necessary. There is also support for DMABUF PipeWire capture, fixes for some streaming crashes and timeouts when Linux is the host system, and support for capturing up to 4K using PipeWire.
For more details, be sure to check out Valve's official announcement via this link.