The newest version of WMCH does not work.
Not sure how to help, since I don't code, I've attached my crash report.
Also according to the mod 'not enough crashes' the crash was caused by 'NullPointerException' and 'RuntimeException'. Yet again, don't know a thing about code, so maybe that is pointless and doesn't help at all.

crash-2022-01-07_22.25.50-server.txt

Love the mod and appreciate the cool updates. I know it must take a lot of effort for all this... so good luck

okay i think i have a fix, but to double check could you send your config file?
on windows, it's located by default at %appdata%\.minecraft\config\wmch.json (copy/paste it into the Run program).

i think it probably has something to do with the config from v1.4, as i changed the field names so it might still be broken.

Woops. Sorry I just saw this. Yeah I can send it if you still need it. I just downloaded the 1.4.2 file and it all seems to be working fine.
You work fast, very impressive