I didn't quite understand the part about summoning troops. The mod wasn't actually intended for the campaign, but since that's what you want, it can be used in the 2nd and 5th missions, but you need to start the mission from the beginning; otherwise, the game will crash when you enter the city.

Summoning troops means calling in reinforcements from the city. I forgot. I thought I would be hiring these troops in the city. But since they can only be obtained at the Fortress, there's no point in upgrading them. It will just be more trouble and a waste of time. We have more important things to do – find runes, capture Elven cities, and then give them away))) But I won't disrupt the author's idea – I will install the mod to allow upgrading in the city.