diff --git a/scripts/upgrade b/scripts/upgrade
index b899082..b44d697 100644
--- a/scripts/upgrade
+++ b/scripts/upgrade
@@ -1,5 +1,8 @@
 #!/bin/bash
 
+# Exit on command errors and treat unset variables as an error
+set -eu
+
 source .fonctions	# Loads the generic functions usually used in the script
 source /usr/share/yunohost/helpers # Source YunoHost helpers