diff --git a/apitypes.py b/apitypes.py
index a3568c5..357549c 100644
--- a/apitypes.py
+++ b/apitypes.py
@@ -61,6 +61,10 @@ class CreateGroupRequest(BaseModel):
 class CreateGroupResponse(BaseModel):
     id: str
 
+class UpdateGroupResult(BaseModel):
+    members_added: List[str]
+    members_removed: List[str]
+
 def test_reaction_message():
     data = """{
         "envelope": {
diff --git a/main.py b/main.py
index 4afd2a1..a3983ec 100644
--- a/main.py
+++ b/main.py
@@ -93,7 +93,7 @@ class SignalAPI:
             print("Failed to remove group members")
             print(r.json())
 
-    def update_group_members(self, group_id: str, other_members: List[str]) -> Result[None, str]:
+    def update_group_members(self, group_id: str, other_members: List[str]) -> Result[UpdateGroupResult, str]:
         group = self.get_group(group_id)
         if is_err(group):
             return Err(group.unwrap_err())
@@ -121,7 +121,7 @@ class SignalAPI:
             if remove_result.is_err():
                 return Err(remove_result.unwrap_err())
 
-        return Ok(None)
+        return Ok(UpdateGroupResult(members_added=members_to_add, members_removed=members_to_remove))
 
     def get_identities(self) -> Result[List[IdentityEntry], str]:
         r = requests.get(f"{self.apiurl}/v1/identities/{self.number}")