--- title: Casualties Unknown Multiplayer Mod: Setup and Co-op Guide description: How to install the Casualties Together co-op mod, what it changes and why friends cannot join. url: https://casualtieswiki.wiki/mods/multiplayer/ --- Mods # Casualties Unknown multiplayer Getting co-op running - 1 **Own the game or demo on Steam**The mod page links the free demo - 2 **Unzip BepInEx 5 x64 into the game root**The folder that holds the game's .exe - 3 **Copy the mod's contents into the game root**Not into a nested folder - 4 **Press Play on Steam**Multiplayer buttons appear in the main menu - 5 **Host a Steam lobby and invite**Every player needs the same mod version _The install order from the mod's own Nexus page, checked on 9 November 2026._ **Short answer:** Casualties Unknown multiplayer only exists as a community mod. Casualties Together (also called KrokMP or the Krokosha mod) adds Steam lobbies, voice chat and co-op healing. Install BepInEx 5, copy the mod into the game folder, and press Play. confirmed The base game is single-player: Steam lists it that way, and players on the forum report that the developer does not plan to add co-op. reported Casualties Together is the mod almost everyone uses, with 143,012 Nexus downloads and 1,166 endorsements on 9 November 2026. confirmed ## Does Casualties Unknown have official multiplayer? No. The [Steam page](https://store.steampowered.com/app/4576490/) lists Single-player and Family Sharing only. confirmed A forum regular summed it up as the developer leaving co-op to modders, and another noted that it is a community mod you use at your own risk. reported Treat any future official support as unannounced: nothing in the official posts through 15 October 2026 mentions it. ## How do you install the Casualties Together mod? These are the steps from the mod’s own page. confirmed - Get the game or the free demo on Steam, and download **BepInEx 5.4.23.5 x64** and the mod’s zip from its Nexus files tab. - In Steam, right-click the game and choose **Manage > Browse local files**. - Unzip BepInEx into that folder, the one with the game’s .exe. - Unzip the mod, open its folder, and move the contents into the same game folder. - Go back to Steam and press **Play**. New multiplayer buttons should appear in the main menu. On Linux, add this to the game’s launch options: `WINEDLLOVERRIDES="winhttp=n,b" %command%`. confirmed The general [mod install guide](https://casualtieswiki.wiki/mods/how-to-install-mods/) covers what to check when BepInEx does not load. Going back to solo play does not need an uninstall. Use the **Deactivate MP Mod** button under Settings > General. confirmed ## What changes when you play together? Co-op is not just the solo game with a friend added. The mod alters survival rules so a shared run stays playable. confirmed | Feature | What it does | | --- | --- | | Steam lobbies | Host and invite through Steam | | Voice chat | In-game voice with effects applied to it | | Point | Middle mouse button marks a location | | Heal others | Right-click to interact with and treat another player | | Share warmth | Standing close shares body temperature | | CPR minigame | Bring back a player in cardiac arrest | | Carry | Move an incapacitated player | | Spectator | Watch after you die | | Sleep | Disabled while the mod is active | | Hunger and thirst | Drain more slowly than in solo | | Unchipped mode | Set per player | Most of these can be adjusted from the in-game console, and the mod can run as a dedicated server, though its page says that is not truly headless. confirmed Because sleeping is off, plan around energy and mood differently from a solo run. The [sleep guide](https://casualtieswiki.wiki/survival/food-water-and-sleep/#sleep) only applies to single-player. ## What are the limits of the mod? The mod’s author is direct about this. There is no client prediction, no network ownership, no deterministic randomness and no anti-cheat. confirmed In practice that means a laggy host affects everyone, and you should only play with people you trust. Save problems are the most common complaint worth planning for. A separate mod, [Multiplayer Inventory Load Fix](https://www.nexusmods.com/scavprototype/mods/177), exists because equipped items could fail to restore when loading a multiplayer save, showing “item too far” errors. confirmed ## Which add-ons work with Casualties Together? Add-ons usually need to be on every machine, and a skin mod needs the host to have it too. confirmed - **[CatPatch](https://www.nexusmods.com/scavprototype/mods/69)**: hugs for a mood boost, sprays and more host controls, with 24,754 downloads. confirmed - **[Multiplayer skins](https://casualtieswiki.wiki/mods/skins/)**: replace how your character looks and sync it to others. - **Simple QoL**: works alone or with the co-op mod on both host and client. confirmed - **Prosthetics**: works if both host and client have it and its requirements, and its author warns of bugs. confirmed ## Why can’t my friends join? Work through these before reinstalling anything. They follow the mod’s install requirements and the general BepInEx checks. - Everyone is on the **same game build and mod version**. The mod was last updated on 8 November, one day before the full release. - BepInEx sits beside the game’s .exe, not inside an extra nested folder. - Add-on mods match between host and client. - The multiplayer buttons appear in the main menu. If they do not, the mod has not loaded, so the problem is the install rather than the network. The mod was built around the demo, and its page still links the demo as the game to download. The full game released on 9 November 2026, so a compatible version may lag behind. Check the mod’s Nexus page for a full-release note before you buy for co-op alone. ## Where do you get help? The mod has its own Discord, linked from its Nexus page, and that is the place for bug reports. Report problems there with your mod version, and try the run without other add-ons first. The [best mods list](https://casualtieswiki.wiki/mods/best-mods/) shows what else is popular once co-op is running. ## Sources Last checked 9 November 2026. Marks: confirmed = official notes, in-game text or a recording of the game; reported = two or more players; unverified = one source. - [Casualties Together on Nexus Mods](https://www.nexusmods.com/scavprototype/mods/67) · install steps, feature list, v5.3.1 - [CatPatch on Nexus Mods](https://www.nexusmods.com/scavprototype/mods/69) - [Multiplayer Inventory Load Fix on Nexus Mods](https://www.nexusmods.com/scavprototype/mods/177) - [Steam forum: official multiplayer plans](https://steamcommunity.com/app/4576490/discussions/0/563672718159387457/) · player reports - [Steam forum: workshop support](https://steamcommunity.com/app/4576490/discussions/0/564797531878420154/) · player reports ## More in Mods - [Best mods The most downloaded mods, what each one changes and how to combine them.](https://casualtieswiki.wiki/mods/best-mods/) - [How to install mods Step-by-step BepInEx setup for Windows, Linux and Steam Deck, and why a mod might not load.](https://casualtieswiki.wiki/mods/how-to-install-mods/) - [Skins Which skin mod to use, how to install skins and how they sync in multiplayer.](https://casualtieswiki.wiki/mods/skins/) - [Console commands How to open the console, which commands are confirmed, and menu mods that replace typing.](https://casualtieswiki.wiki/mods/console-commands/)