Hi. I added the mod to my existing savegame (4 hour progress in this save), so I have already researched some techs (steel, for example). The problem is that I do not have the mod's tech unlocked for the research I have already completed. For example, I have researched steel before adding the mod, but now I can not make mechanical spare parts. I can make Machine Oil, since it was its own research.

A potential/suggested fix would be to maybe give each item its own research?

Thank you for this hint! This is an issue caused by a missing recipe update. I'm sorry for this - I'll provide a fix as soon as possible.

Creating new techs for each maintenance item is feasable but not necessary at the moment. But I'll think about it.

Thank you. I have also noticed that adding the mod to an existing save, does not bring the current buildings into maintenance mode. Those buildings function as if they are still in vanilla (although this is a minor problem IMO).