diff --git a/doc/release-notes.md b/doc/release-notes.md
index a29094b51..ae28b011a 100644
--- a/doc/release-notes.md
+++ b/doc/release-notes.md
@@ -4,3 +4,13 @@ release-notes at release time)
 Notable changes
 ===============
 
+This release fixes a security issue described at
+https://z.cash/support/security/announcements/security-announcement-2019-09-24/ .
+
+
+Shrinking of debug.log files is temporarily disabled
+----------------------------------------------------
+
+In previous versions, `zcashd` would shrink the `debug.log` file to 200 KB on
+startup if it was larger than 10 MB. This behaviour, and the `-shrinkdebugfile`
+option that controlled it, has been disabled.