diff --git a/fledermaus_formatter/main.py b/fledermaus_formatter/main.py
index 74afffc..121b03b 100644
--- a/fledermaus_formatter/main.py
+++ b/fledermaus_formatter/main.py
@@ -47,6 +47,7 @@ def main():
     # Directory mode
     parser.add_argument("--input-dir", help="Input directory")
     parser.add_argument("--output-dir", help="Output directory")
+    parser.add_argument("-s", help="Serial mode", action="store_true")
 
     parser.add_argument(
         "-t", "--type",
@@ -58,7 +59,7 @@ def main():
     args = parser.parse_args()
 
     if args.v:
-        print("1.1")
+        print("1.2")
         return
     if not args.type:
         parser.error("The --type argument is required.")
@@ -85,7 +86,7 @@ def main():
 
                 tasks.append((input_path, output_path, args.type))
 
-        max_workers = os.cpu_count() or 1
+        max_workers = os.cpu_count() or 1 if not args.s else 1 
         logger.info(f"Processing {len(tasks)} files using {max_workers} workers")
 
         with ProcessPoolExecutor(max_workers=max_workers) as executor: