diff --git a/packages/stompman/stompman/serde.py b/packages/stompman/stompman/serde.py
index a99d917a..fbfaa43b 100644
--- a/packages/stompman/stompman/serde.py
+++ b/packages/stompman/stompman/serde.py
@@ -46,7 +46,7 @@
 }
 
 
-def iter_bytes(bytes_: bytes) -> tuple[bytes, ...]:
+def iter_bytes(bytes_: bytes | bytearray) -> tuple[bytes, ...]:
     return struct.unpack(f"{len(bytes_)!s}c", bytes_)
 
 
diff --git a/pyproject.toml b/pyproject.toml
index 646f9ea6..8f908d48 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -8,7 +8,7 @@ dev = [
     "anyio==4.8.0",
     "faker==37.5.3",
     "hypothesis==6.124.7",
-    "mypy==1.14.1",
+    "mypy==1.17.1",
     "polyfactory==2.19.0",
     "pytest==8.3.4",
     "pytest-cov==6.0.0",