diff --git a/scripts/upgrade b/scripts/upgrade
index a0bb1d8..5729eac 100644
--- a/scripts/upgrade
+++ b/scripts/upgrade
@@ -29,6 +29,15 @@ port=$(ynh_app_setting_get --app=$app --key=port)
 
 upgrade_type=$(ynh_check_app_version_changed)
 
+#=================================================
+# ENSURE DOWNWARD COMPATIBILITY
+#=================================================
+
+if ynh_compare_current_package_version --comparison lt --version 12.105.0~ynh1
+then
+	ynh_die --message="Sorry, this version is not upgradable to the latest version :("
+fi
+
 #=================================================
 # BACKUP BEFORE UPGRADE THEN ACTIVE TRAP
 #=================================================