Exchange 2013 metadata update

Our self hosted exchange 2013 server was setup using a domain we no longer want to use. We have since changed our domain and emails are sending/receiving fine using this new domain but our metadata still reflects the old domain. We need someone to make the necessary changes so the following can be updated.
Received: from SERVERNAME.local.olddomainname.com (X.X.X.X) by SERVERNAME.local.olddomainname.com (X.X.X.X) with Microsoft SMTP Server (TLS)