diff --git a/src/docs/user/configuration/configuring_outbound_email.diviner b/src/docs/user/configuration/configuring_outbound_email.diviner
--- a/src/docs/user/configuration/configuring_outbound_email.diviner
+++ b/src/docs/user/configuration/configuring_outbound_email.diviner
@@ -240,6 +240,7 @@
 To use this mailer, set `type` to `smtp`, then configure these `options`:
 
   - `host`: Required string. The hostname of your SMTP server.
+  - `port`: Optional int. The port to connect to on your SMTP server.
   - `user`: Optional string. Username used for authentication.
   - `password`: Optional string. Password for authentication.
   - `protocol`: Optional string. Set to `tls` or `ssl` if necessary. Use