diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 159cccd..3aa2025 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -25,7 +25,7 @@ repos:
           - '--fix'
       - id: ruff-format
   - repo: 'https://github.com/pre-commit/mirrors-mypy'
-    rev: v1.20.2
+    rev: v2.0.0
     hooks:
       - id: mypy
         additional_dependencies:
diff --git a/proxystore_ex/connectors/dim/margo.py b/proxystore_ex/connectors/dim/margo.py
index be4dc2a..36fec3c 100644
--- a/proxystore_ex/connectors/dim/margo.py
+++ b/proxystore_ex/connectors/dim/margo.py
@@ -394,7 +394,7 @@ class MargoServer:
     """MargoServer implementation."""
 
     def __init__(self, engine: Engine) -> None:
-        self.data: dict[str, bytes] = {}
+        self.data: dict[str, BytesLike] = {}
         self.engine = engine
 
     def evict(
diff --git a/testing/mocked/pymargo.py b/testing/mocked/pymargo.py
index f081d8d..babd895 100644
--- a/testing/mocked/pymargo.py
+++ b/testing/mocked/pymargo.py
@@ -14,7 +14,7 @@
 server = 'server'
 
 # server dictionary
-data_dict: dict[str, bytes] = {}
+data_dict: dict[str, bytes | bytearray] = {}
 
 
 class MargoException(Exception):  # pragma: no cover  # noqa: N818