10 critical crash bugs -- 6 networked multiplayer bugs -- About 30 interface bugs -- Over 100 game-rule bugs.
Play against a random number of opponents -- Play with auto designed ships -- 6th ship design slot -- Greatly improved build queue management -- Unbuy function -- New hotkeys.
1.50 improved -- Version 1.2 mod -- ICE -- VDC -- Melee -- Lots of mapmods -- A standard mode is available, which is only the patch, no mods.
Modding with plain text configuration files -- Lua scripting support -- Integrated mapgen functionality.
Supports English, German, French, Spanish and Italian DOS editions of MOO2. -- Installing 1.50 does not break current version 1.31 or 1.40 installations. No original files are overwritten.
Fan patch. February 6, 2021. 10132 kB zip file
Development of the 1.50 patch for Master of Orion II: Battle at Antares (MOO2) started in 2015, and the first version 1.50.0 was released on February 6, 2016. Currently the patch stands at version 220.127.116.11 and a version 1.50.19 is in the works. The download is a zip file that includes the patch, mods and the MOO2 Launcher.
Fan patch. November 9, 2020. 1178 kB zip file
For testing with the 1.40 patch I use this version. It has 4 changes compared to b23: Screen switches are faster; Tactical Combat is enabled by default in the Game Setup screen; missiles default to x2 shot racks instead of x5 in the Design Dock console; and the ALT+menlo cheat gives 30.000 instead of 9.999 research points. The zip file includes a changelog and the source code of the 1.40 patch.
Fan patch. May 22, 2006. 30 kB zip file
The English DOS version sold online is fan patch 1.40b23 by Lord Brazen from May 2006. Information about this patch can be found in Lord Brazen's 1.40 patch FAQ.
In case you do not want to play a fan patch you can revert from 1.40b23 to the last official patch as follows: Download English version 1.31 patch (below), extract the file "ORION2.EXE" from the zip file and copy it into your MOO2 directory.
Microprose patch. April 11, 1997. 3350 kB zip file
Microprose patch. April 11, 1997. 2342 kB zip file
Version 1.31 or higher is required for installing the 1.50 patch. There are no official patches for the French, Spanish and Italian editions because they already released at version 1.31.
Microprose patch. March 3, 1997. 3294 kB zip file
There is no version 1.3 patch for the German edition because it already released at version 1.3.
Microprose patch. November 25, 1996. 4425 kB zip file
Version 1.2 was distributed as a patcher program that would patch six v1.1 files. This download includes the original patcher program as well as the six patched files.
The default mod of the 1.50 patch. Introduces new combat mechanics like Ship Initiative 2.0, Interactive Combat Stats (ICS) and Simplified Beam Formula. Makes various tweaks to weapons and special systems. Special care was given to improve AI ship designs. The Excel manual included with the download explains it all. The Tech Tree is unchanged from Classic.
Version 1.2 mod
This little mod approximates MOO2 version 1.2 as close as possible with current 1.50 config: Creative costs 6 picks again, Psilon race design restored, original Guardian and Antaran ship designs, Plasma Cannon, Ion Cannon and Gyro Destabilizer weapon stats set back to original values.
Designed for single player games, making the AI much more challenging. This mod changes race picks & Tech Tree extensively. The difference between ICE-M and ICE-X is AI strength: ICE-X Impossible has the strongest AI, you'd better know what you are doing!
This mod is designed for 1v1 multiplayer and is included with the 1.50 patch. A new version of the mod might suddenly appear in between 1.50 releases. The latest version can be found on the Nirran's page.
1.50 multiplayer  NEW!
New mod that builds on 1.50 improved. Race picks are based on the old DemoDict mod by Siron. The Tech Tree is modified to make morale techs more accessible. No Orion star, nor any splinter colonies on the map. Follow the installation instructions from the included Readme.
Spiral galaxy mod 1.0  NEW!
Mod by Epirasque that creates a spiral galaxy, one arm per player with their home world at the tip.
Techtree mods 1.0
Bundle of Lua mods by Epirasque. Contains several mods that alter the research tech tree or otherwise interact with how players acquire tech through research. Follow the installation instructions from the included Readme.
No AI surrender mod
Micromod that prevents AI from surrendering before turn 1000. Unzip the No AI surrender mod and place the config file in 150\mods\150\, then restart MOO2 Launcher.
Savegame Editor. Corion version 1.1.1 has been optimized for the 1.50 patch. 153 kB zip file.
LBX editor suite by Grig de Griz. Handles text, picture and font files. Includes a leader editor. 2713 kB zip file.
O2M 4.02 page
Thread on CivFanatics for the modding tool and game launcher by Ponkyo. Includes a tech tree editor.
O2M is not fully compatible with MOO2 Launcher. If you want to use both, then create 2 separate MOO2 game directories, one for each launcher.
Official website of DOSBox. Emulator to run MOO2 on modern machines.