diff --git a/scripts/viewer/sync_viser_message_defs.py b/scripts/viewer/sync_viser_message_defs.py
index 452621ddc..369836acb 100644
--- a/scripts/viewer/sync_viser_message_defs.py
+++ b/scripts/viewer/sync_viser_message_defs.py
@@ -1,6 +1,7 @@
 """Generate viser message definitions for TypeScript, by parsing Python dataclasses."""
+import json
 import pathlib
-import subprocess
+from datetime import datetime
 
 import tyro
 from viser.infra import generate_typescript_interfaces
@@ -23,13 +24,24 @@ def main() -> None:
         "nerfstudio/viewer/app/src/modules/WebSocket/ViserMessages.tsx"
     )
     assert target_path.exists()
-    target_path.write_text(defs, encoding="utf_8")
-    print(f"Wrote to {target_path}")
 
-    # Run prettier.
-    # TODO: if this is not installed maybe we should print some error with installation
-    # instructions?
-    subprocess.run(args=["prettier", "-w", str(target_path)], check=False)
+    old_defs = target_path.read_text(encoding="utf_8")
+
+    if old_defs != defs:
+        target_path.write_text(defs, encoding="utf_8")
+
+        with open("nerfstudio/viewer/app/package.json", "r", encoding="utf_8") as f:
+            data = json.load(f)
+
+        now = datetime.now()
+        data["version"] = now.strftime("%y-%m-%d") + "-0"
+
+        with open("nerfstudio/viewer/app/package.json", "w", encoding="utf_8") as f:
+            json.dump(data, f, indent=2)
+        print(f"Wrote updates to {target_path}")
+        print(f"Current viewer version is now {data['version']}")
+    else:
+        print("No update to messages.")
 
 
 def entrypoint() -> None: