Have you performed isolation testing?
Yes, it's not working when only Simply Swords and it's dependencies are installed.

Describe the bug
Error loading mods.

To Reproduce
Steps to reproduce the behavior:

1. Install Neoforge core 21.1.186.
2. Install latest version of simplyswords (1.60.12-1.21.1)
3. Install latest version of dependencies.
4. Launch minecraft.
5. See error.

Expected behavior
Minecraft starting and me being able to play.

Screenshots

Additional Info:

• Modloader: NeoForge
• Modloader Version: 21.1.186
• Minecraft Version: 1.21.1
• Mod Version: 1.60.12
• Environment: minecraft client

Additional context
1.16.11 does not have this issue.
Crash log:
crash-2025-07-03_07.49.27-fml.txt

got same issue:
https://mclo.gs/bNw0BI3

Thanks for the reports!
This is fixed as of RosemaryThymes PR: #267
Version 1.60.13 is now live on CurseForge and Modrinth