Valve have pushed out a Steam Play beta update with Proton 3.16-7 now available for testing. Lots of fixes!

Not quite the huge upgrade many were expecting, most people thought Valve would be pushing ahead with a major update of Wine but this release still seems like a very nice update overall

Firstly, they've updated DXVK to 0.96 and FAudio to 19.02. This should hopefully mean quite a number of games will see improvements and begin working. Additionally, there has been some controller improvements, with Unity specifically mentioned for games like Subnautica and INSIDE.

As for bug fixes and other changes, here's what they improved:

Fix for fullscreen behavior in Into The Breach.

Fix for crashes in some d3d9 games on Mesa.

Fix for crash when launching certain games, including Path of Exile, the Bloons series, and the Naruto Shippuden series.

Fix for games with special characters in paths, including LEGO Harry Potter.

Restore previous functionality of the Uplay client.

New runtime option for old games that can't handle modern GL extension strings. Set PROTON_OLD_GL_STRING to limit the extension string length.

New runtime option to disable d3d10 support, PROTON_NO_D3D10.

Better support for games that use very old steamworks SDKs, including Lost Planet.

Fixed various problems with the build system, and added a new top-level Makefile to make simple builds much easier.

You can see the changelog here. Looks like it's going to be a fun weekend of testing ahead!

If you're having issues updating, you can select Proton from Steam's tools menu found when you hover over "LIBRARY" -> "TOOLS" and search for "Proton" then install "Proton 3.16 Beta". Seems many people have had issues with it not updating properly.

After some fresh testing, with a forced Proton update I can confirm Into the Breach fullscreen now works as expected—hooray!