diff --git a/debian/changelog b/debian/changelog
index 37ca60ab..7de5604c 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,11 @@
+livecd-rootfs (2.557) disco; urgency=medium
+
+  * Don't install gpg or gpg-agent when building buildd images for series
+    earlier than bionic.  (In earlier series, those packages didn't exist
+    and gnupg was build-essential.)
+
+ -- Colin Watson <cjwatson@ubuntu.com>  Wed, 16 Jan 2019 12:50:39 +0000
+
 livecd-rootfs (2.556) disco; urgency=medium
 
   * Add wpasupplicant to the additional packages installed for the raspi2 and
diff --git a/live-build/auto/config b/live-build/auto/config
index c99ab05f..e81eb948 100755
--- a/live-build/auto/config
+++ b/live-build/auto/config
@@ -686,8 +686,15 @@ case $SUBPROJECT in
 		add_package install policyrcd-script-zg2
 		add_package install pkgbinarymangler
 		add_package install ca-certificates
-		add_package install gpg
-		add_package install gpg-agent
+		case $SUITE in
+			precise|trusty|xenial)
+				;;
+			*)
+				# only needed in >= bionic
+				add_package install gpg
+				add_package install gpg-agent
+				;;
+		esac
 		case $SUITE in
 			precise|trusty|xenial)
 				# no longer needed in >= artful