diff --git a/RELEASE_NOTES.md b/RELEASE_NOTES.md
index 35db7b1..cd8a93a 100644
--- a/RELEASE_NOTES.md
+++ b/RELEASE_NOTES.md
@@ -8,6 +8,8 @@ Fixed a bug that caused some notifications to be lost when coming from a user in
 
 Added an additional check for blocked instances.
 
+On OpenBSD, if the `disable_email_notifications` server flag is set to `true`, `unveil()` is not called for the execution of the `/usr/sbin/sendmail` binary and `pledge()` doesn't set the `exec` promise.
+
 ## 2.50
 
 Incoming posts can now be filtered out by content using regular expressions on a server level (these regexes are written in the `filter_reject.txt` file at the server base directory; see `snac(5)` and `snac(8)`).