diff --git a/Whatsapp_Chat_Exporter/__main__.py b/Whatsapp_Chat_Exporter/__main__.py
index e693727..a62d317 100644
--- a/Whatsapp_Chat_Exporter/__main__.py
+++ b/Whatsapp_Chat_Exporter/__main__.py
@@ -269,7 +269,7 @@ def validate_args(parser: ArgumentParser, args) -> None:
     # Basic validation checks
     if args.android and args.ios and args.exported and args.import_json:
         parser.error("You must define only one device type.")
-    if not args.android and not args.ios and not args.exported and not args.import_json:
+    if not args.android and not args.ios and not args.exported and not args.import_json and not args.incremental_merge:
         parser.error("You must define the device type.")
     if args.no_html and not args.json and not args.text_format:
         parser.error("You must either specify a JSON output file, text file output directory or enable HTML output.")
@@ -748,7 +748,14 @@ def main():
                 args.wa = "ContactsV2.sqlite"
         
         if args.incremental_merge:
-            incremental_merge(args.source_dir, args.target_dir, args.media)
+            incremental_merge(
+                args.source_dir,
+                args.target_dir,
+                args.media,
+                args.pretty_print_json,
+                args.avoid_encoding_json
+            )
+            print("Incremental merge completed successfully.")
         else:        
             # Process contacts
             process_contacts(args, data, contact_store)
@@ -766,4 +773,4 @@ def main():
 
 
 if __name__ == "__main__":
-    main()
\ No newline at end of file
+    main()
diff --git a/Whatsapp_Chat_Exporter/utility.py b/Whatsapp_Chat_Exporter/utility.py
index 3e5e70f..b3303bd 100644
--- a/Whatsapp_Chat_Exporter/utility.py
+++ b/Whatsapp_Chat_Exporter/utility.py
@@ -259,7 +259,7 @@ def import_from_json(json_file: str, data: Dict[str, ChatStore]):
         print(f"Importing chats from JSON...({index + 1}/{total_row_number})", end="\r")
 
 
-def incremental_merge(source_dir: str, target_dir: str, media_dir: str):
+def incremental_merge(source_dir: str, target_dir: str, media_dir: str, pretty_print_json: int, avoid_encoding_json: bool):
     """Merges JSON files from the source directory into the target directory.
 
     Args:
@@ -303,7 +303,12 @@ def incremental_merge(source_dir: str, target_dir: str, media_dir: str):
                 if json.dumps(merged_data, sort_keys=True) != json.dumps(target_data, sort_keys=True):
                     print(f"Changes detected in '{json_file}', updating target file...")
                     with open(target_path, 'w') as merged_file:
-                        json.dump(merged_data, merged_file, indent=2)
+                        json.dump(
+                            merged_data,
+                            merged_file,
+                            indent=pretty_print_json,
+                            ensure_ascii=not avoid_encoding_json,
+                        )
                 else:
                     print(f"No changes detected in '{json_file}', skipping update.")