Proton Experimental gets fixes for ARM64, EA App, Modern Warfare 2 (2009)
21 Sep 2026 at 5:05 pm UTC By Liam Squires-HandA fresh update is here for Proton Experimental to get even more Windows games working on SteamOS / Linux. The what? A reminder for you - Proton Experimental is a…
By Liam Squires-Hand
A fresh update is here for Proton Experimental to get even more Windows games working on SteamOS / Linux.
The what? A reminder for you - Proton Experimental is a compatibility layer to run Windows games on Linux systems like Steam Machine, Steam Deck and Desktop Linux. This one is like their testing ground for future stable numbered version Proton updates. You can install any version of Proton by just searching for "Proton" in your Steam Library. Check out the GamingOnLinux Guide to all the different Proton versions if you're confused.
For the September 21st update:
Key Changes- Fixed Ragnarok: The New World to be playable on other devices than Steam Decks.
- Fixed Winning Post 9 not accepting Japanese kana input.
- Fixed video playback in Making Lovers.
- Fixed EA App Launcher login window not being focused properly with Gamescope.
- Fixed VITAL not being able to close redist installer with Xalia.
- Fixed Fallout: New Vegas incorrectly highlighting some options in the launcher with Xalia.
- Fixed Call of Duty: Modern Warfare 2 (2009) Safe Mode window popup not working with Xalia.
- Disabled Xalia for Final Fantasy XI's gamepad configuration window to avoid interfering with built-in controller support.
- Updated Wine Mono to 11.3.0.
- Updated Xalia to 0.5.0.
- Fixed Proton 11 regressions:
- Deus Ex: Mankind Divided should be playable again with AMD GPUs.
And also here's the changes from Wine Mono 11.3 and Xalia 0.5 that help with ARM64 (for devices like the Steam Frame) along with other tweaks and fixes:
Wine Mono 11.3.0- An ARM64 build has been added. This includes a new port of Mono to ARM64 Windows. Several components, not including the Mono runtime itself, are also built as arm64ec.
- Mono
- Fixed premature end of stream when reading line-by-line using legacy VB6 compatibility APIs (Wine bug 59908).
- Imported some System.Management.Instrumentation types from reference source (MR 240).
- Fixed a regression in Path.GetFullPath introduced in the previous release (MR 241).
- Upstream updates
- llvm-mingw to 20260616.
- SDL to 3.4.14.
- FNA to 26.08.
- Added support for win32 scrollbar controls.
- Include controls supporting UIAutomation in the heuristic for Winforms container controls.
- Added app-specific logic for Call of Duty: Modern Warfare 2 (2009), Final Fantasy XI gamepad config tool, PlayOnline gamepad config tool, WiX installers, RefRain config tool, Memories Off #5, Kega Fusion, FreestyleFootball R, and HITMAN World of Assassination.
- Disabled for Deus Ex: Mankind Divided.
- Windows developers can now set a __xalia_ignore or __xalia_supports_gamepad property to mark windows that should be ignored by Xalia.
- Fixed the main loop polling and consuming CPU for no reason. (Oddly, SDL does this when an application doesn't create an SDL window, even though it's not clear why it needs a window.).
- Static win32 controls used as containers are now properly handled.
- For win32 combo boxes, the A button now simulates an enter keypress instead of asking the control to collapse the combo box. This fixes inability to make selections in HITMAN World of Assassination, which apparently has custom behavior that looks for an enter keypress specifically.
- Static win32 controls that have the WS_TABSTOP style are no longer targetable by default, since they have no builtin handling of keyboard focus.
- An ARM64 build has been added.