diff --git a/stdlib/imaplib.pyi b/stdlib/imaplib.pyi
index bd3d0777db15..54760dd036ca 100644
--- a/stdlib/imaplib.pyi
+++ b/stdlib/imaplib.pyi
@@ -1,7 +1,7 @@
 import subprocess
 import sys
 import time
-from _typeshed import Self
+from _typeshed import ReadableBuffer, Self
 from builtins import list as _list  # conflicts with a method named "list"
 from collections.abc import Callable
 from datetime import datetime
@@ -9,7 +9,7 @@ from re import Pattern
 from socket import socket as _socket
 from ssl import SSLContext, SSLSocket
 from types import TracebackType
-from typing import IO, Any
+from typing import IO, Any, SupportsAbs, SupportsInt
 from typing_extensions import Literal, TypeAlias
 
 __all__ = ["IMAP4", "IMAP4_stream", "Internaldate2tuple", "Int2AP", "ParseFlags", "Time2Internaldate", "IMAP4_SSL"]
@@ -54,12 +54,12 @@ class IMAP4:
     file: IO[str] | IO[bytes]
     def read(self, size: int) -> bytes: ...
     def readline(self) -> bytes: ...
-    def send(self, data: bytes) -> None: ...
+    def send(self, data: ReadableBuffer) -> None: ...
     def shutdown(self) -> None: ...
     def socket(self) -> _socket: ...
     def recent(self) -> _CommandResults: ...
     def response(self, code: str) -> _CommandResults: ...
-    def append(self, mailbox: str, flags: str, date_time: str, message: bytes) -> str: ...
+    def append(self, mailbox: str, flags: str, date_time: str, message: ReadableBuffer) -> str: ...
     def authenticate(self, mechanism: str, authobject: Callable[[bytes], bytes | None]) -> tuple[str, str]: ...
     def capability(self) -> _CommandResults: ...
     def check(self) -> _CommandResults: ...
@@ -157,7 +157,7 @@ class _Authenticator:
     def encode(self, inp: bytes) -> str: ...
     def decode(self, inp: str) -> bytes: ...
 
-def Internaldate2tuple(resp: bytes) -> time.struct_time: ...
-def Int2AP(num: int) -> str: ...
-def ParseFlags(resp: bytes) -> tuple[bytes, ...]: ...
+def Internaldate2tuple(resp: ReadableBuffer) -> time.struct_time | None: ...
+def Int2AP(num: SupportsAbs[SupportsInt]) -> bytes: ...
+def ParseFlags(resp: ReadableBuffer) -> tuple[bytes, ...]: ...
 def Time2Internaldate(date_time: float | time.struct_time | time._TimeTuple | datetime | str) -> str: ...