What Is the IW4-SP Client and How Do You Install It?

IW4-SP is AlterWare's single-player mod client for Call of Duty: Modern Warfare 2. It restores features that were removed from the original release, patches known exploits, and adds modding support, so you can play the MW2 campaign with restored content and community-made modifications. You get it by downloading the AlterWare Launcher, which handles the download and updates for you. This is the single-player client — it is separate from the multiplayer IW4 client, so don't expect it to connect you to online matches.

What the IW4-SP Client Does

AlterWare describes its clients around a few core ideas, and IW4-SP fits into that same framework:

• Restored features — content and functionality that the original developers removed are brought back.
• Additional content — extra weapons and maps ported from other games expand what's available.
• Security patches — exploits present in the Steam versions are patched.
• Modding support — advanced modding capabilities let the community create and share new content.
• Dedicated servers — you can host your own or join community-hosted ones, with a full server browser.

For IW4-SP specifically, the focus is the Modern Warfare 2 single-player experience. The "SP" in the name signals that this is the single-player variant, not the multiplayer client.

How to Install IW4-SP

The supported path is through the AlterWare Launcher, which automatically downloads and updates the client.

1. Download the AlterWare Launcher from the AlterWare site. The launcher is the recommended method because it manages downloads and keeps the client updated automatically.
2. Run the launcher and let it fetch the IW4-SP client. The launcher handles IW4-SP, IW5-Mod, IW6-Mod, and S1-Mod clients.
3. Follow the installation guide if you hit any snags. AlterWare points users to a detailed installation guide on its forum.

If you prefer a manual route for other clients, note that the T7x client for Black Ops 3 is distributed differently — it's a standalone client you place in your BO3 game directory and run. That's a separate product from IW4-SP, so don't mix the two up.

Verifying It Works

Once installed, launch the client and confirm it loads the MW2 single-player content. Because the launcher updates automatically, you generally don't need to re-download manually after the first install.

Common Points of Confusion

• IW4-SP vs. the multiplayer IW4 client — these are different. IW4-SP is for single-player. If you want multiplayer, you need the multiplayer client, not this one.
• Steam version vs. AlterWare client — the AlterWare client patches exploits that exist in the Steam version, so it's not simply a re-launcher for the Steam build.
• Where to get help — AlterWare runs a Discord server with over 16,500 members and a support forum. Both are listed as community and support channels on the site.

Supported Games at a Glance

Bottom Line

If you want to play Modern Warfare 2's single-player campaign with restored features, exploit patches, and mod support, IW4-SP is the client for it, and the AlterWare Launcher is the intended way to install and keep it updated. If you're after multiplayer, look at the separate multiplayer client instead. For installation problems, the AlterWare forum guide and Discord are the places to go.