Updated RELEASE_NOTES.

RELEASE_NOTES.md

@@ -1,5 +1,9 @@
 # Release Notes
 
+## UNRELEASED
+
+Fixed regression while sending email via pipe on OpenBSD.
+
 ## 2.78
 
 Hashtag following also allow URLs to RSS feeds of ActivityPub objects (like e.g. https://mastodon.social/tags/ThankYouTuesday).