When I load the old version: I can clean my own chat.
When I load this version: I cannot clear my own chat, and I'm unsure if I've cleared the global, 'cuz my own chat doesn't clear on /cleanchat or /cleanall.
I do get an error about /cleanall when I tried without the permission. I do not get an error when I try /cleanchat without permissions.

By default, admin are excluded from chat clearing, so you'd need to disable that if you are admin and want your chat to clear.