diff --git a/update_gwr_advance_ticket_date.py b/update_gwr_advance_ticket_date.py
index 2e24bb9..2a02e3d 100755
--- a/update_gwr_advance_ticket_date.py
+++ b/update_gwr_advance_ticket_date.py
@@ -24,6 +24,10 @@ def send_mail(subject: str, body: str) -> None:
     msg["Date"] = formatdate()
     msg["Message-ID"] = make_msgid()
 
+    # Add extra mail headers
+    for header, value in config.getattr("MAIL_HEADERS", []):
+        msg[header] = value
+
     msg.set_content(body)
 
     s = smtplib.SMTP(config.SMTP_HOST)