Call of Duty (2003) - game versions explained

If you're getting into Call of Duty 1 multiplayer today, the first thing to understand is which version to run. There are two active scenes - 1.5 (the final official patch, and what Steam installs) and 1.1 with CoDExtended - and they are not compatible with each other. A 1.5 client can only join 1.5 servers, and a 1.1 client can only join 1.1 servers, so which version you want depends on which servers you want to play on.

A Brief History

When Call of Duty launched in 2003, patches came steadily - 1.1, 1.2, 1.3, 1.4, and finally 1.5 in December 2004. Patch 1.5 added PunkBuster anti-cheat, tournament commands, and HTTP mod downloads. During the ClanBase and ESL era (2004-2012), version 1.5 with PunkBuster was the competitive standard: leagues required PB-enabled servers, and most serious players ran 1.5.

Then two things happened in 2013:

• PunkBuster dropped CoD1 support. Activision's contract with EvenBalance expired and wasn't renewed. PB update servers went offline, breaking anti-cheat on 1.5 servers.
• ClanBase shut down. One of the main competitive platforms for CoD1 closed.

With no league forcing PunkBuster, the CoDExtended project launched that same year - a community-built patch that gave version 1.1 modern features without the dead PunkBuster dependency. A large community grew up around 1.1 + CoDExtended. But 1.5 did not disappear: it stayed the Steam default and kept an active player base, so today the two scenes run side by side rather than one having replaced the other.

The Two Versions That Matter Today

Version 1.5 (Steam default)

This is what Steam installs automatically, and it was the final official patch. It is actively played - the in-game server browser still works, and it hosts competitive and rifle-only communities among others. If you bought CoD1 on Steam, you can jump straight into 1.5 servers with no changes.

Version 1.1 + CoDExtended

Version 1.1 with CoDExtended (also called 1.1x or codx) is a separate active scene built on a community patch. CoDExtended adds:

• Fast HTTP mod downloads (no more waiting ages for maps)
• Fixes the "invalid CD-Key" errors
• No CD-key required on most servers - just download and play
• Discord Rich Presence (shows what server you're playing on)
• Unlocked FOV
• FPS counter and connection info overlay
• Anti-cheat measures (replacing the dead PunkBuster)
• Stability and security fixes against known engine exploits

You can review the source code on GitHub. Because it is a different version from 1.5, its servers are a separate population - a 1.5 client cannot see or join them, and vice versa.

Which Should I Run?

It depends on where you want to play. Both versions have live servers, so the simplest approach is to look at the live CoD1 server list, see which servers are populated, and match their version:

• Playing on Steam and happy with the built-in server browser, or joining a competitive/rifle community? 1.5 is ready to go, no changes needed.
• Want the CoDExtended servers specifically (fast downloads, no CD-key hassle, extra quality-of-life)? Go 1.1 + CoDExtended.

You can also keep both installed in separate folders if you play on servers from each scene.

How to Check Your Version

The version number is shown in the bottom-right corner of the multiplayer menu. You can also open the console with ~ - the version appears in the header line.

• 1.5 - Steam default, active scene, no changes needed to play 1.5 servers
• 1.1 - install CoDExtended to join the 1.1x scene
• 1.1x - CoDExtended installed, you're set for the 1.1 scene

Setup Guide

Staying on 1.5 (Steam default)

Nothing to do - Steam already installs 1.5. Launch the game and open the multiplayer server browser.

Switching to 1.1 + CoDExtended (from Steam's 1.5)

1. Download the downgrade tool from cod1x.eu
2. Find your CoD install folder (right-click in Steam, Manage, Browse Local Files)
3. Extract the downgrade files into that folder
4. Run downgrade.bat
5. Download the CoDExtended client from the same site and extract it into the game folder

Launch through Steam as normal - you'll be on 1.1 with CoDExtended.

CD Install (version 1.0 to 1.1)

The retail CD installs the unpatched version (1.0). To join the 1.1 + CoDExtended scene:

1. Download the 1.1 patch from cod.pm or cod1x.eu
2. Run the patch installer or extract over your CoD folder
3. Install the CoDExtended client on top

Full Patch History

• 1.0 (Oct 2003) - original retail release
• 1.1 (Late 2003) - first multiplayer patch. Base of the CoDExtended (1.1x) scene
• 1.2 (Early 2004) - smaller teammate icons, exploit fixes, removed menu music
• 1.3 (Mid 2004) - added mp_bocage and mp_neuville, fixed prone+lean exploit, EAX 3 audio
• 1.4 (2004) - PunkBuster support added. Used by early ClanBase rules
• 1.5 (Dec 2004) - added mp_tigertown, PB server browser UI, HTTP mod redirects, tournament scripting commands. The final official patch and the competitive standard of the ClanBase/ESL era, still active today
• 1.51 (2004) - United Offensive expansion only, not for base CoD1

FAQ

Should I run 1.5 or 1.1 + CoDExtended?

Whichever your servers use. Both are active, but they're incompatible - you can only connect to servers running your exact version. If you play on Steam's built-in browser or in a competitive/rifle community, 1.5 is ready to go. If you want the CoDExtended servers (fast downloads, no CD-key hassle, modern anti-cheat), go 1.1 + CoDExtended. Check the live CoD1 server list to see what's populated.

Can I play on 1.1 servers with version 1.5?

No. The versions are incompatible - you can only connect to servers running your same version. That's the main reason to decide up front which scene you're joining.

Do I need a CD key?

On 1.1 + CoDExtended servers: usually no - most don't enforce CD-key checks. On 1.5: it depends on the server's settings, the same as any official-patch server.

Is CoDExtended safe?

Yes. It's open-source, maintained by the community, and has been around for years. The client is a DLL placed in your game folder - no separate launcher needed.