Article taken from GamingOnLinux.com.

This is the big one. Steam have released a major update of the Steam client which not only adds in some big new features, it also drastically improves the Linux client.* Improved interactions between the Steam runtime and host distribution libraries, which should let Steam work out of the box with open-source graphics drivers on modern distributions. If using an older distribution or running into problems, use STEAM_RUNTIME_PREFER_HOST_LIBRARIES=0 to revert to previous behavior.This next one is particularly fun, as I specifically wrote about it being an issue for nearly 4 years. Shortly after that article Valve sought to fix it.* Unify close-to-tray behavior with other platforms. If using a distribution that doesn't have proper compatible tray support, use STEAM_FRAME_FORCE_CLOSE=0* Added idle detection, friend status will now automatically switch to Away/Snooze* Fixed Steam not obeying SIGTERM, Steam will now gracefully exit when logging out of a session* Fixed keyboard input and cursor switching in overlay for Vulkan applications* Update Vulkan loader in the Steam runtime to enable Xlib support* Updated libxcb in the runtime with a fix for DRI3-related crashes on open-source graphics driversSteam now supports Xbox 360, Xbox One, and Generic X-Input controller configurator support. So you can custom-map them like you do with the Steam Controller. They also added support for the Emio PS4 "Elite" controller.It seems Steam will attempt to give you a recommend configuration based on the type of controller you have plugged in too, which is ideal.Game install folders can be moved to other Steam Library folders under Properties / Local Files. I mentioned this before from the Beta, as it's really useful for people like me who split their library across an SSD or a bigger cheaper HDD depending on what game it is. Some games really are better on an SSD.An interesting one is this:* Added support for using the overlay keyboard for games that have launchers.Hopefully this means on SteamOS that games with launchers might be a bit more usable now, as it would make the SteamOS experience more pleasant too.It's fantastic to see that Valve has done a pretty decent pass at making the Linux client better. More like this in 2017 please Valve.See the full update notes here