From f99574b72319566d2601b5d5b27068404d2b4df1 Mon Sep 17 00:00:00 2001
From: Daniel James <daniel@64studio.com>
Date: Thu, 2 Aug 2012 15:00:12 +0100
Subject: [PATCH] Check that old version exists before deciding this is an
 upgrade

---
 debian/postinst | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/debian/postinst b/debian/postinst
index 6426484c9..637d9bf52 100755
--- a/debian/postinst
+++ b/debian/postinst
@@ -209,7 +209,7 @@ case "$1" in
       echo "Reconfiguration complete."
     else
 
-      if [[ "${OLDVERSION:0:3}" < "1.9" ]]; then
+      if [ -n "$OLDVERSION" ] && [[ "${OLDVERSION:0:3}" < "1.9" ]]; then
         echo "Upgrades from Airtime versions before 1.9.0 are not supported. Please back up your files and perform a clean install."
       else