What is IW4x on iw4x.io?

Updated

IW4x is a multiplayer client for Call of Duty: Modern Warfare 2 (2009), distributed through iw4x.io. The site offers two versions of the client, each built around a different way to play: IW4x, which centers on community-hosted dedicated servers, and IW4x (mm), which uses matchmaking with friends and parties available directly in the client. The site itself provides downloads, documentation, community links, and a frequently asked questions section.

What the site offers

iw4x.io is the project's home for:

  • Downloads — client builds for both versions
  • Documentation — setup and reference material
  • Community — links to Discord and GitHub
  • FAQ — answers to common questions about the client
  • Release archive — earlier client builds kept for reference

IW4x vs. IW4x (mm)

The two versions differ mainly in how you find and join games.

IW4x IW4x (mm)
Core model Community-hosted dedicated servers Matchmaking
Server rules and mods Each server can set its own Not the focus
Playing with friends Join the same server, or host one for friends Friends list and parties in the client

Both support mods, but mods are optional — you can install either client and play without touching them.

System requirements

The site lists a baseline for client and server use:

Requirement Client Server
Processor Intel Pentium 4 3.2 GHz or AMD Athlon 64 3200+ 2 cores
Memory 1 GB About 500 MB per server
Graphics 256 MB GeForce 6600GT or Radeon 1600XT Not required
Storage 12 GB available space —
Connection Broadband internet Upload at least 5–10 megabits per second
Network — Port forwarding or firewall access

Open source and development

IW4x is open source. Anyone can read the code and follow how it changes, and development happens in public on GitHub. The site points to two ways to get involved: start with an open issue, or write down what you learned for the next person. A contributor guide is also available.

Release archive

Earlier client builds are kept for reference. Recent entries listed on the site include r5146 and r5145 (September 19, 2026), r5144 (September 18, 2026), r5124 (September 14, 2026), and r5123 (September 10, 2026), each with a changelog and download link.

Which client should you use?

It comes down to how you want to play. Choose IW4x if you want community-run dedicated servers with their own rules and mods. Choose IW4x (mm) if you prefer matchmaking and want a built-in friends list and parties for playing together. Either way, you can play with friends.