diff --git a/scripts/upgrade b/scripts/upgrade
index 5150b98..9235598 100755
--- a/scripts/upgrade
+++ b/scripts/upgrade
@@ -42,7 +42,11 @@ final_path=/var/www/$app
 sudo mkdir -p $final_path
 sudo cp -a ../sources/* $final_path
 sudo cp ../conf/dokuwiki.php $final_path/conf
-sudo cp ../conf/acl.auth.php $final_path/conf
+
+# Do not override ACL configuration file
+if [ ! -f "$final_path/conf/acl.auth.php" ]; then
+    sudo cp ../conf/acl.auth.php $final_path/conf
+fi
 
 # Remove upgrade notification
 # See https://www.dokuwiki.org/update_check