diff --git a/debian/preinst b/debian/preinst
index a7a5c7a54..198b8aee6 100755
--- a/debian/preinst
+++ b/debian/preinst
@@ -25,6 +25,9 @@ case "$1" in
     service nginx reload
     ;;
 
+  upgrade)
+    ;;
+
   abort-upgrade)
     ;;