

Plotocol Support made it possible to connect with 1.12 even with 1.13 server, but the plugin did not work with the following error.

So they see theirselves as the entity but nobody else does.

Removing the moreplayermodels.entities permission from players still allows them to turn into entities on their client, but it wont be updated to players anymore. To prevent people from seeing 'secret chats' in chatbubbles, set the EnableChatBubbles to false in the config file.
