Space Empires IV is designed to allow mods to be installed in subfolders of the root SEIV folder. This means that you can easily use custom data files without having to change any default files.

Each mod should go into its own folder. If you are installing Adamant Mod, for example, you will want to install it into an Adamant subfolder of the folder where SEIV is installed. The name of the folder does not actually matter (except that it can not be the name of a normal SEIV folder that already exists). Most mods will include a default installation folder, so you can just unzip them into the SEIV folder. But, be careful that the mod is not going to install itself over the default Data folder.

To use a mod, locate the file Path.txt in the same folder as the SE4.exe. Open it up. There is one operable line, which is as follows:

Using Mod Directory := None

To load a mod, simply change "None" in this line to the name of the folder in which the mod is located. For example, if you have the Adamant Mod installed, you would replace "None" with "Adamant." The line would then look like this:

Using Mod Directory := Adamant

Alternatively, you can use the Mod Launcher (created by Matryx). Install it into the SEIV folder, and then run it. It will list all the mods you have installed, as well as savegames in each mod folder (and the stock folder). The program automatically overwrites the Path.txt file and then launches SEIV for you, and so is much more convenient to use.

The following is borrowed from Malfador.com:

The first Space Empires game was created by Aaron Hall in 1993 as a pet project based on his love for other space strategy games such as Star Fleet Battles, Master Of Orion, Starfire, and Wing Commander. After playing around with that game, Aaron decided to add features and make this prototype a bit more playable. After a year of work, the game was interesting enough that with a little more work, it could be public worthy. In 1995, Aaron Hall formed the company known as “Malfador Machinations” to release the game Space Empires II out into the world as shareware. With primitive graphics, but a fun play style, the game was met with acclaim by fans from all over the world.

With the welcome reception it received, the next title for Malfador Machinations was clear. In 1996, the company added a new employee Russell Saito (long-time friend) to help with design and artwork. Over the course of the next 2 years, Space Empires III was developed and then released in 1997. This game had the advanced features of customizable graphics and data files, detailed ship orders, and a large galaxy play-field. Though not a widely known game, the game did very well as another shareware product. Once again, the fans were outspoken in their love for this small-shop game.

In the summer of 1998, Malfador Machinations began development on Space Empires IV. The goal was to have industry competitive graphics, a simplified user-interface, and simultaneous play capabilities. With the addition of several new artists who were fans of the game, the development pushed onward. After 2 years of development work and outstanding suggestions from their large user base, Space Empires IV was completed in July of 2000. Not only did it meet all of the original goals set for it, but it also expanded on the large feature set of Space Empires III, by adding new unit types, technologies, and political relations. Space Empires IV is the culmination of a seven year process.