diff --git a/docs/releasenotes.rst b/docs/releasenotes.rst
index 44bbe3d9956c4cddb6504c00a472295d6e825287..564da60edbc393ee68ff7cf49cefc69f7335c7da 100644
--- a/docs/releasenotes.rst
+++ b/docs/releasenotes.rst
@@ -60,6 +60,8 @@ upgrade to Python 3.x, dropping support for Python 2.7.
     dropped. This could introduce incompatibility with older clients
     trying to connect to the IMAP/SMTP server.
 
+  * Dropped the use of ``procmail`` for local mail deliveries.
+
 * ``php_website`` role
 
   * Parameter ``enforce_https`` has been deprecated and
@@ -129,6 +131,12 @@ upgrade to Python 3.x, dropping support for Python 2.7.
   * Run apticron at least once during initial installation to avoid
     accidental locking later on during the same playbook run.
 
+* ``mail_server`` role
+
+  * Fixed the problem with the SMTP server (Postfix) not using TLS at
+    all for outgoing SMTP connections. The server will now default to
+    using opportunistic TLS (using TLS where available).
+
 * ``wsgi_website`` role
 
   * Deploy the requirement files used for upgrade checks to correct
@@ -155,6 +163,9 @@ upgrade to Python 3.x, dropping support for Python 2.7.
     limit for the SMTP server to accept via
     ``mail_message_size_limit`` role parameter.
 
+  * Mail server configuration has been slightly updated to better
+    match what is currently the defaults in Debian Stretch.
+
 * ``xmpp_server`` role
 
   * Server now supports blocking users via `XEP-0191: Blocking Command