Mayhem is a mod where you are not just a pilot, you are the leader of a rising empire and as such, you must conquer sectors and build ships and stations by collecting resources and making your own enemies and allies. This is a pure sandbox gameplay, but there is pressure. If you decide to stay in your home sector, you will eventually be attacked by a growing fleet of OCV, so you need to be aggressive and expand your empire to other sectors... Craft your weapons, stations and ships, manage your factories, invade enemy territories, and defend your sectors with giant fleets and static platforms in a chaotic universe!
The E/I module is sometimes necessary to update your previous Mayhem savegames. Please read the full instructions. Install in X3\addon\scripts.
Install in X3\addon\scripts.
And that's it, you have nothing else to do, except configuring your hotkeys again (or switching profile).
Always check if an E/I if needed from a version to another in the changelog.