Minecraft v1.15.2
Forge v31.2.36
Ars Nouveau v0.20.1

My server crashed during load after updating to the new version.
Crash Report

Oh sorry about that, if you revert to 0.20 that should fix it for now.

Yep, already have for now.

I have released the fix here: https://www.curseforge.com/minecraft/mc-mods/ars-nouveau/files/3071984

Thanks!