This mod relies on and bundles Kotlin 1.3.0, and makes use of experimental features at the time of development (unsigned types), and so when other mods bundle Kotlin 1.5.30, this mod breaks due to the unsigned types methods having changed.
It would be great if you could compile against and bundle a more recent version.

a

I'm currently working on trying to jury-rig together a new build, but I need to update gradle to update kotlin, which means I need to update ForgeGradle, which is a nightmare, so it may be a bit.

Any progress on this?

Unfortunately not. Work has been stressful lately, so I've had very little motivation for working on personal projects. Especially stressful and mentally taxing projects like this one.

Gotcha. Prioritize work and irl over a Minecraft mod. It's way more important with your mental health and all that. Hope things become better soon ❤️😁

There's currently an updated version of Forgelin calls Forgelin Continuous (I'm the author of it), and there's no additional content compared to original one, so you may probably want to give it a try.

Link: https://www.curseforge.com/minecraft/mc-mods/forgelin-continuous

Yeah, that was my plan, but in order to compile against newer kotlin stdlib versions I have to use newer versions of gradle, which requires upgrading forgegradle, which is a nightmare.