diff --git a/upgrade.sh b/upgrade.sh
index 91753cea..e42213f0 100755
--- a/upgrade.sh
+++ b/upgrade.sh
@@ -47,7 +47,7 @@ else
     fi
 fi
 
-case "$DIST" in
+case "$SYSTEM" in
 unknown)    echo The upgrade script will not work on this OS.
             echo Try a manual upgrade instead.
             exit