Hi, I tried fixing this mod for 2.0...

I changed data-final-fixes.lua line 74 from:

else

to

elseif technology.unit then

and it seems to work fine for me. Specifically, technology.unit can now be nil if technology.research_trigger is set instead https://lua-api.factorio.com/latest/prototypes/TechnologyPrototype.html#research_trigger That's for things like having research unlock after the player places a certain number of buildings or after mining a certain number of resources. So I think it's okay to just ignore those for the purposes of the tree trimming.

I haven't updated this mod to 2.0 because the game does the main part of the mod in vanilla now, which is to remove unnecessary prerequisite connections. I don't see a demand for updating it yet, as there haven't been any updated or new mods that add science packs that have problems with missing prerequisites. Ideally I wouldn't have to update this mod at all, and mods that add new science packs get it right the first time.

Oh okay, I didn't know about the changes in 2.0 vanilla. I was using this because of https://mods.factorio.com/mod/KetsInfiniteTechnologies which adds extra technologies that don't have prerequisites correctly added. But I can probably help them fix that mod to add the prerequisites correctly. That sounds like a better way to fix things.

As another example, I found this mod useful with Pyanodons for streamlining the tech tree so that more advanced techs (e.g. oil-gathering, uranium-mining) have their connections pushed further down the tree where they "belong".