This version brings support to Steam Input, meaning full gamepad support on both Windows and Linux, but... although it works for the full version of the game (which is not released yet), I haven't been able to convince Steam that playtest also supports it.
This means that the build has everything needed to make it work, but there's something missing on the Steamworks settings side of things.

As a side effect, the Xbox gamepads that were working on Windows in the previous builds now stopped working completely.