SteamOS 3.9 has landed for everyone. Valve released SteamOS 3.9.5 to the stable channel on 24 October (Australian time), and its notes are blunt about it: "SteamOS 3.9.5 has just been released for all users." If you're on a Steam Deck, a Steam Machine or a supported handheld, it's the version to grab.
Because the notes cover everything since the last stable release, SteamOS 3.8, this is a big one. Here's what matters.
The big-ticket changes
- A fresh desktop. Desktop Mode moves from Plasma 6.4.3 to Plasma 6.7.3, on an updated Arch Linux base. If you spend any time in Desktop Mode, it's a three-version jump.
- A new kernel. Valve has rebased on Linux 7.2.
- Hibernation, sort of. There's preliminary hibernation support, but it isn't in the Game Mode UI yet and is "not yet enabled on Steam Deck due to an outstanding driver bug." Don't go looking for it on a Deck just yet.
- Better WiFi. The default WiFi backend switches to wpa_supplicant, which Valve says improves compatibility with various networks, and Valve has added fast reconnect on resume from sleep. A bug that stopped hidden networks connecting on the first try is fixed too.
- Security. Valve has revoked compromised eMudhra CA certificates, alongside general security and stability updates.
- Steam Frame. Improved support for the Steam Frame wireless adapter.
Fixes by device
GamingOnLinux, which covered the release the same day, picked out the device-specific fixes, and Valve's notes list them in full:
- Steam Deck: lower idle power use when no audio is playing.
- Steam Machine: Remote Play now works when booting with no external display, firmware updates no longer occasionally fail to apply, and STAR WARS: Galactic Racer no longer has performance problems after resuming from suspend.
- Legion Go 2: no more crash when launching Forza Horizon 6, plus preliminary brightness control.
- Intel Panther Lake PCs: games including ELDEN RING and DARK SOULS III now run, and boot-screen corruption is fixed.
- Some ASUS devices: a workaround for fans running too fast after waking from sleep.
Frame-limiter fixes are in there too. The "Disable Frame Limiter" toggle now works with VRR, frame limits no longer drag FPS below target on certain external displays, and the limiter no longer wrongly applies to VR titles streamed from a Steam Machine to a Steam Frame.
A few smaller changes round it out. Valve has updated the bootloader to improve compatibility with certain motherboards, the Desktop Mode lock screen can now be enabled in settings (it stays off by default), and logging in to Desktop Mode over RDP with system users works again when enabled.
What to do
On a Steam Deck or other SteamOS device on the stable channel, open Settings, check for system updates and install 3.9.5, then reboot.
A couple of honest caveats. Valve's notes don't put numbers on the idle power improvement, so don't expect a specific battery gain. And if you depended on the older iwd WiFi backend's behaviour, the switch to wpa_supplicant is the change to watch.
Valve hasn't announced the next SteamOS release, so for now 3.9.5 is the version to be on.
Reporting notes