# Proton (software)

Proton is a compatibility layer that allows Windows software (primarily video games) to run on Linux-based operating systems. Proton is developed by Valve in cooperation with developers from CodeWeavers. It is a collection of software and libraries combined with a patched version of Wine to improve performance and compatibility with Windows games. Proton is designed for integration into the Steam client as "Steam Play". It is officially distributed through the client, although third-party forks can be manually installed.

## Overview

Proton was initially released on 21 August 2018. Upon release, Valve announced a list of 27 games that were tested and certified to perform like their native Windows counterparts without requiring end-user tweaking. These include Doom (2016), Quake, and Final Fantasy VI.
Proton incorporates several libraries that improve 3D performance. These include Direct3D-to-Vulkan translation layers, namely DXVK for Direct3D 9, 10 and 11, and VKD3D-Proton for Direct3D 12. A separate library known as D9VK handled Direct3D 9 support until it was merged into DXVK in December 2019.

## Compatibility

Being a fork of Wine, Proton maintains very similar compatibility with Windows applications as its upstream counterpart. In addition to the official list of compatible games, many other Windows games are compatible, albeit unofficially, with Proton. The user can optionally force use of Proton for a specific game, even if a Linux version already exists. This may be done when a game's native Linux support is lacking or unstable.

### ProtonDB

ProtonDB is an unofficial community website that collects and displays crowdsourced data describing the compatibility of a given title with Proton, on a rating scale from "Borked" (doesn't work) to "Platinum" (works perfectly). The site is inspired by the WineHQ AppDB, which also collects and displays crowdsourced compatibility reports and uses a similar rating system.

## Release history

Valve has released nine major versions of Proton. The versioning scheme refers to the upstream Wine version it's based on, with an appended patch number.
Proton generally lags behind its upstream Wine base by several releases. Unofficial forks, such as Proton GE, have been created to rebase Proton on recent Wine versions, which may improve or worsen compatibility with games compared to the official release.
In December 2020, Valve released Proton Experimental, a perpetual beta branch of Proton that incorporates new features and bug fixes quicker than regular releases, which are eventually included in a regular release.
The Steam Deck uses Proton to increase software title compatibility.

### Proton 3.7 (August 2018)

First official release of Proton. Supported 27 games, including DOOM (2016), Quake, and Final Fantasy VI. Integrated DXVK for Direct3D 10/11 implementation via Vulkan.

### Proton 4.2 (April 2019)

Updated to a newer version of Wine, improving compatibility and performance. Enhanced support for fullscreen mode and controllers.

### Proton 5.0 (February 2020)

Based on Wine 5.0, bringing major improvements to game compatibility. Improved support for games with anti-cheat systems.

### Proton 5.13 (October 2020)

Introduced compatibility for more games and improved support for existing titles. Enhanced media playback and networking features.

### Proton 6.3 (April 2021)

Based on Wine 6.0 with additional patches. Improved Direct3D 12 support via VKD3D-Proton. Better game performance and compatibility.

### Proton 7.0 (February 2022)

Built on Wine 7.0. Significant improvements to game compatibility and new features.

### Proton 8.0 (April 2023)

Continued enhancements to game compatibility and performance. Updated DXVK and VKD3D-Proton for improved graphics support.

### Proton 9.0 (October 2024)

Latest major release focusing on stability and compatibility. Improved support for newer games and technologies.