I am working right now on replacing some of the out-dated plugins on the server with newer alternatives. Already updated are the Essentials and EssentialsSpawn plugins that manage level-based spawn points and several other commands that recently broke.
I am now working on replacing the complete Chat plugin. I will try to replicate our currrent environment as much as possible with alternative plugins. This will take a bit of time to understand and mirror all the configurations 1:1, so the chat might not be working as expected until then. Please be patient.