diff --git a/stdlib/2and3/mailbox.pyi b/stdlib/2and3/mailbox.pyi
index 5745f65d1..0793f27f9 100644
--- a/stdlib/2and3/mailbox.pyi
+++ b/stdlib/2and3/mailbox.pyi
@@ -20,10 +20,10 @@ _MessageType = TypeVar("_MessageType", bound=Message)
 _MessageData = Union[email.message.Message, bytes, str, IO[str], IO[bytes]]
 
 class _HasIteritems(Protocol):
-    def iteritems(self) -> Iterator[Tuple[str, Message]]: ...
+    def iteritems(self) -> Iterator[Tuple[str, _MessageData]]: ...
 
 class _HasItems(Protocol):
-    def items(self) -> Iterator[Tuple[str, Message]]: ...
+    def items(self) -> Iterator[Tuple[str, _MessageData]]: ...
 
 linesep: bytes
 
@@ -63,7 +63,7 @@ class Mailbox(Generic[_MessageType]):
     @overload
     def pop(self, key: str, default: _T = ...) -> Union[_MessageType, _T]: ...
     def popitem(self) -> Tuple[str, _MessageType]: ...
-    def update(self, arg: Optional[Union[_HasIteritems, _HasItems, Iterable[Tuple[str, _MessageType]]]] = ...) -> None: ...
+    def update(self, arg: Optional[Union[_HasIteritems, _HasItems, Iterable[Tuple[str, _MessageData]]]] = ...) -> None: ...
     def flush(self) -> None: ...
     def lock(self) -> None: ...
     def unlock(self) -> None: ...