Okay so, I'm using AAI Loaders, im not sure if the mod works upgrading with those loaders by default - i assume it does, but i also use another mod, loader utilities, gives loaders the ability to stack, but changes them by default. This mod does not work with that, doesn't throw an error, just doesn't do anything.

https://i.imgur.com/NznakUG.gif

So, this is an interesting one. First, the author does not assign upgrade targets to the modified loaders. Therefore, even if I added support, it wouldn't change the behaviour – my mod ignores belt items that don't have an upgrade target specified. I also do not think the way they make separate entities (see more detail below) will allow the loaders to be upgraded without a very hacky implementation, since it is different entities but the base prototype data remains unchanged.

The second issue relates to how the mod author set that each configuration of the loader (w.r.t. the loader settings) is a different object. Why that is the case, you'll have to ask him. But that means that I cannot easily figure out what the loader related to a tier is supposed to be, or what tier a loader is supposed to be related to, since there are at least 4 different options in this case. I will continue looking at potential solutions for this, but I do not expect a quick solution, unfortunately.

I will send a message to them, as well, thank you.

I can add upgrade targets - this was ignored because it's not useable by players. Is that all that's required?

Also, are you raising built and setting last user when upgrading? If so we'll need an extra layer of compat

Right, my mod now supports Loader Utilities' many loaders (from version 1.5.0). However, there is a caveat: it won't work because of a game engine limitation that hidden items (i.e., all the "new" loaders created by Loader Utilities) cannot be upgraded by planner or by script. So unless I do something very hacky that will be breaking a lot of rules and gameplay loops, I cannot support them properly.

Like i mentioned on the bug report, you can set the mod setting "lu-show-all-loaders" to hidden and forced_value to true so that they show up and can be used, no caveat required.