For some reason, whenever I put my custom music disc (Specifically from the mod Etched), I can't put it in, yet the discs from Vanilla Minecraft (And probably other modded discs but I haven't investigated that yet) can. I think this might be some sort of incompatibility between Sophisticated Backpacks and Etched.

To Reproduce
Steps to reproduce the behavior:

1. Open backpack
2. Click on custom music disc
3. Drag it to the Jukebox upgrade slot
4. The same custom music disc does not go in the slot

Expected behavior
The custom music disc from Etched to be put on the jukebox upgrade slot and also play music

Versions
3.20.3.1029
forge: 47.2.0

This specifically requires adding compatibility layer because etched adds that to vanilla classes but obviously doesn't to sophisticated ones. I have that on my list to add in the future.

Given that we now have sounds stored in components in 1.21 if Etched ports it should use those and custom disks should just work in jukebox upgrade so I am closing this.