What is SteamDew?

SteamDew is a mod specifically for Steam multiplayer, which rewrites the networking backend of Stardew Valley.

This provides the following benefits:

• Eliminates most multiplayer disconnects (In Vanilla, we disconnected ~2 times per hour. With SteamDew, we had no disconnects at all)
• Reduces bandwidth requirements of the game (Vanilla uses no compression. In SteamDew, we compress large packets, often by 250%+)
• More consistent latency between client & server (Less jittery movements for other players, reduced teleporting of cave enemies)
• Faster transitions when moving between locations, and quicker load times when joining the game or starting a new day
  

If you and your friends are playing on Steam, then SteamDew is a must-have mod, especially if you are playing on an unstable connection, or if you want to play larger content mods that add more data to your save file.

All players (especially the server) must have SteamDew to experience its advantages.

However, we designed SteamDew to be as convenient as possible. As such, vanilla clients can connect to a SteamDew server, and SteamDew clients can connect to vanilla servers. This means you do not need to remove SteamDew to play with anyone else, on any platform. It is strictly an upgrade to the original networking backend of Stardew Valley.

Installation

• Install the latest version of SMAPI (3.18.6)
• Download* and unzip the mod. Copy the folder to your Mods folder
• Run the game
  

*Your browser may block the download due to the way SteamDew works. We assure you it is safe, and you can check the VirusTotal analysis if you are unsure.

Do not install SteamDew if you do not own the game on Steam. It will not work. It will also not work with the Legacy 32-bit beta version of Stardew Valley.

Compatibility

SteamDew uses Harmony to inject the rewritten network backend into Stardew Valley. Usually, Harmony patches would cause potential compatibility issues with other mods. However, there are likely no sane mods that will patch the Stardew Valley network backend like we do, especially none that patch SMAPI itself.

As such, SteamDew should be compatible with:

• Stardew Valley 1.5.6
• Stardew Valley 1.6 Alpha (For modders. May need to be compiled from source Recent changes in the 1.6 Alpha have made SteamDew unnecessary!)
• All mods (We inject SMAPI itself to allow all mods to use our networking backend)
• Windows 64-bit, Linux 64-bit, and MacOS (See MacOS issues below)
• Multiplayer (Won't do anything for LAN, and works for cross-platform play)
• Single-player (It will not do anything)
  

SteamDew is well-tested and should be stable. We have used it on very unstable internet connections, and on several laptops, PCs, and Macs. It can support connections to & from Vanilla games (even those without SMAPI at all), and will still work for cross-platform play for GoG Galaxy & Gamepass PC players (though they will not get the advantages of SteamDew).

If you encounter any issues with SteamDew, whether with cross-platform play or compatibility with other mods, feel free to let me know. Please upload the SMAPI log if possible.

The instructions for finding & uploading the SMAPI log are here:
https://smapi.io/log

MacOS

For compression, we use the open-source library LZ4 which is under the BSD-2 Clause License. We specifically use prebuilt binaries from the Lightweight Java Game Library (LWJGL), which is under the BSD-3 Clause License.

Due to the default security settings of MacOS, it will block the dynamic library file "liblwjgl_lz4.dylib" when you first try to launch the game with SteamDew installed. Here is a support article for how to allow this file to be loaded: https://support.apple.com/en-us/HT202491#openanyway

As mentioned before, you can see the VirusTotal analysis if you have any concerns about the safety of SteamDew.

Source Code

Link: https://github.com/myuusubi/SteamDew

The README of the repository goes into greater detail of how SteamDew works on a technical level.