This is a mod for Heroes of Might and Magic 3 Complete, with the Horn of the Abyss mod. It is recommended you also use the HD mod, and the 1.5.4 version of Horn of the Abyss to avoid any unforseen issues. It changes many aspects (primary skills, secondary skills, spells and some descriptions) with the purpose of having more valid ways of playing the game as you progress through it. It is stable and you can also play it with others in hotseat or LAN/Online, as long as the people you play with also have this mod installed. Check the raw files for the changelog and check out the "All official campaigns" addon available for download here.
These are the raw files in the place of a changelog. It includes all the changes made, except for the secondary skill changes (although you can see the new descriptions of the skills, as per the changes made, in the SSTRAITS.txt included)