diff --git a/docs/rolereference.rst b/docs/rolereference.rst
index 195eeb0cf59128a3889d887ca2da0a858254adf3..20f2be3a761b9902019f4e22dbf798ee4d5ebddb 100644
--- a/docs/rolereference.rst
+++ b/docs/rolereference.rst
@@ -1113,6 +1113,13 @@ Parameters
 **mail_ldap_dovecot_password** (string, mandatory)
   Password for authenticating the Dovecot LDAP user.
 
+**mail_message_size_limit** (integer, optional, ``10240000``)
+  Maximum size of message in bytes that the SMTP server should accept
+  for incoming mails. If the mail message size exceeds the listed
+  value, it will be rejected by the server. The size is also
+  advertised as part of SMTP server capabilities (in response to the
+  ``ehlo`` SMTP command).
+
 **mail_server_tls_protocols** (list, optional, ``[ "TLSv1.2" ]``)
   List of TLS protocols the mail server should support. Each value specified
   should be compatible with Postfix configuration option