diff --git a/basecamp_client.py b/basecamp_client.py
index fc1e697..35dc48e 100644
--- a/basecamp_client.py
+++ b/basecamp_client.py
@@ -201,7 +201,7 @@ class BasecampClient:
             raise Exception(f"Failed to create todo: {response.status_code} - {response.text}")
 
     def update_todo(self, project_id, todo_id, content=None, description=None, assignee_ids=None,
-                    completion_subscriber_ids=None, due_on=None, starts_on=None):
+                    completion_subscriber_ids=None, notify=None, due_on=None, starts_on=None):
         """
         Update an existing todo item.
         
@@ -212,6 +212,7 @@ class BasecampClient:
             description (str, optional): HTML description
             assignee_ids (list, optional): List of person IDs to assign
             completion_subscriber_ids (list, optional): List of person IDs to notify on completion
+            notify (bool, optional): Whether to notify assignees
             due_on (str, optional): Due date in YYYY-MM-DD format
             starts_on (str, optional): Start date in YYYY-MM-DD format
             
@@ -221,18 +222,23 @@ class BasecampClient:
         endpoint = f'buckets/{project_id}/todos/{todo_id}.json'
         data = {}
         
-        if content:
+        if content is not None:
             data['content'] = content
-        if description:
+        if description is not None:
             data['description'] = description
-        if assignee_ids:
+        if assignee_ids is not None:
             data['assignee_ids'] = assignee_ids
-        if completion_subscriber_ids:
+        if completion_subscriber_ids is not None:
             data['completion_subscriber_ids'] = completion_subscriber_ids
-        if due_on:
+        if notify is not None:
+            data['notify'] = notify
+        if due_on is not None:
             data['due_on'] = due_on
-        if starts_on:
+        if starts_on is not None:
             data['starts_on'] = starts_on
+
+        if not data:
+            raise ValueError("No fields provided to update")
             
         response = self.put(endpoint, data)
         if response.status_code == 200: