diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 649aca24b..cd5bd2637 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -35,7 +35,7 @@ repos:
     -   id: reorder-python-imports
         args: [--py3-plus]
 -   repo: https://github.com/asottile/add-trailing-comma
-    rev: v2.0.2
+    rev: v2.1.0
     hooks:
     -   id: add-trailing-comma
         args: [--py36-plus]
@@ -44,7 +44,7 @@ repos:
     hooks:
     -   id: setup-cfg-fmt
 -   repo: https://github.com/pre-commit/mirrors-mypy
-    rev: v0.790
+    rev: v0.800
     hooks:
     -   id: mypy
         exclude: ^testing/resources/
diff --git a/pre_commit/file_lock.py b/pre_commit/file_lock.py
index 5e7a05862..55a8eb29c 100644
--- a/pre_commit/file_lock.py
+++ b/pre_commit/file_lock.py
@@ -1,11 +1,11 @@
 import contextlib
 import errno
-import os
+import sys
 from typing import Callable
 from typing import Generator
 
 
-if os.name == 'nt':  # pragma: no cover (windows)
+if sys.platform == 'win32':  # pragma: no cover (windows)
     import msvcrt
 
     # https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/locking