added a prerm script to explicitly fail if someone attempts to downgrade to anything...

diff --git a/packaging/debian/monkeysphere.prerm b/packaging/debian/monkeysphere.prerm
new file mode 100755 (executable)
index 0000000..1a5135a
--- /dev/null
+++ b/packaging/debian/monkeysphere.prerm
@@ -0,0 +1,36 @@
+#!/bin/sh -e
+
+# prerm script for monkeysphere
+
+# the only thing we're doing here is making sure that the local
+# administrator is not trying to downgrade to a version below 0.23,
+# since there was such a major reorganization of system data during
+# the transition to 0.23.
+
+# Author: Daniel Kahn Gillmor <dkg@fifthhorseman.net>
+# Copyright 2009
+
+set -e
+
+case "$1" in
+    upgrade)
+       if dpkg --compare-versions "$2" lt 0.23 ; then
+           cat >&2 <<EOF
+
+Downgrading the monkeysphere to a version earlier than 0.23 can have
+BAD CONSEQUENCES, including potentially locking you out of the system.
+Downgrading in this fashion is NOT SUPPORTED.
+
+EOF
+
+           exit 1
+       fi
+    ;;
+esac
+
+# dh_installdeb will replace this with shell code automatically
+# generated by other debhelper scripts.
+
+#DEBHELPER#
+
+exit 0