IMAP LOGIN command using literals, but not supported on backend

Hi,

I have an NGINX setup that is terminating SSL on the frontend and passing through to the backend IMAP server. When the client sends a command like "4 LOGIN username password", the corresponding command being sent by NGINX to the backend is "4 LOGIN {15}". NGINX is converting and using literals, unfortunately, the backend does not support this.

Is there a way to have NGINX just pass the LOGIN command as received, without using literals?

Thank you,
Louis