Units cannot upgrade from swordsmen to swordsmen, from Galleys to Kogg, from Quadriema to Galeas, and so on with others. This concerns additional universal* units; units unique to each civilization work fine. Also, I noticed that ALL universal* units do not support buffs, for example: (+5 strength from the Oligarchy, + 5 strength from the coast/shallow waters (Japan’s ability)) any ideas what this is connected with and how to fix it? Could it be that I'm playing with a BBG mod that changes everything for everyone? Or because of the many mods for the wonders of nature and light? - I doubt. Could it be because of the Sukritact mod group?